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4L30-E
H Y
D R A
- M A
T I C CONTENTSINTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
HOW TO USE THIS BOOK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
UNDERSTANDING THE GRAPHICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
TRANSMISSION CUTAWAY VIEW (FOLDOUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PRINCIPLES OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A
MAJ OR MECHANICAL COMPONENTS (FOLDOUT) . . . . . . . . . . . . . . . . . . . 10
RANGE REFERENCE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
TORQUE CONVERTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
APPLY COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
PLANETARY GEAR SETS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
HYDRAULIC CONTROL COMPONENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
ELECTRONIC CONTROL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
POWER FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
COMPLETE HYDRAULIC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
LUBRICATION POINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
BUSHING, BEARING & WASHER LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
SEAL LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
ILLUSTRATED PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
BASIC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
PRODUCT DESIGNATION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
2
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PREFACE
All information contained in this book is based on the latest data availableat the time of publication approval. The right is reserved to make product orpublication changes, at any time, without notice.
No part of any Powertrain publication may be reproduced, stored inany retrieval system or transmitted in any form or by any means,
including but not limited to electronic, mechanical, photocopying, re-cording or otherwise, without the prior written permission of PowertrainDivision of General Motors Corp. This includes all text, illustrations,tables and charts.
©COPYRIGHT 1992 POWERTRAIN DIVISION
General Motors Corporation
ALL RIGHTS RESERVED
The Hydra-matic 4L30-E Technician’s Guide is primarily intended forautomotive technicians that have some familiarization with an automatictransaxle or transmission. Other persons using this book may find thispublication somewhat technically complex if additional instruction is notprovided. Since the intent of this book is to explain the fundamental me-chanical, hydraulic and electrical operating principles, some of the termi-nology used is specific to the transmission industry. Therefore, wordscommonly associated with a specific transaxle or transmission functionhave been defined as needed throughout this publication.
The Hydra-matic 4L30-E Technician’s Guide is intended to assist techni-cians during the service, diagnosis and repair of this transmission. How-
ever, this book is not intended to be a substitute for other service publicationsthat are normally used on the job. Since there is a wide range of repairprocedures and technical specifications specific to certain vehicles andtransmission models, the proper service publication must be referred towhen servicing the Hydra-matic 4L30-E transmission.
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The Hydra-matic 4L30-E Technician’s Guide is an-other Hydra-matic publication from the Technician’sGuide series. These publications provide in-depthtechnical information that is useful when learning orteaching the fundamental operations of a transaxle ortransmission. This book is designed to graphicallyillustrate and explain the function of the mechanical,hydraulic, and electrical systems that make up theHydra-matic 4L30-E transmission. The information
contained in this book was developed to be useful forboth the inexperienced and experienced technician.The inexperienced technician will find the explana-tions of the basic operating characteristics of thistransmission as valuable when learning the functionof each component used in this transmission. Theexperienced technician will find that this book is avaluable reference source when diagnosing a prob-lem with the vehicle.
In the first section of this book entitled “Principles of Operation”, exacting explanations of the major com-ponents and their functions are presented. In everysituation possible, text describes component opera-tion during the apply and release cycle as well assituations where it has no effect at all. The descrip-tive text is then supported by numerous graphic illus-trations which further emphasize the operational theo-ries presented.
The second major section entitled “Power Flow”,blends the information presented in the “Principlesof Operation” section into the complete transmissionassembly. The transfer of torque from the engine
through the transmission is graphically displayed ona full page while a narrative description is providedon a facing half page. The opposite side of the half page contains the narrative description of the hydrau-lic fluid as it applies components or shifts valves inthe system. Facing this partial page is a hydraulicschematic that shows the position of valves,checkballs, etc., as they function in a specific gearrange.
The third major section of this book displays the“Complete Hydraulic Circuit” for specific gear ranges.Foldout pages containing fluid flow schematics andtwo dimensional illustrations of major componentsgraphically display hydraulic circuits. This informa-tion is extremely useful when tracing fluid circuitsfor learning or diagnosis purposes.
The “Appendix” section of this book provides addi-tional transmission information regarding lubricationcircuits, seal locations, illustrated parts lists and more.Although this information is available in currentmodel year Service Manuals, its inclusion providesfor a quick reference guide that is useful to the tech-nician.
Production of the Hydra-matic 4L30-E Technician’sGuide was made possible through the combined ef-forts of many staff areas within the General MotorsPowertrain Division. As a result, the Hydra-matic4L30-E Technician’s Guide was written to providethe user with the most current, concise and usableinformation available with regards to this product.
INTRODUCTION
3
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HOW TO USE THIS BOOK
Principles of Operation section by showingspecific fluid circuits that enable the mechanicalcomponents to operate. The mechanical powerflow is graphically displayed on a full size pageand followed by a half page of descriptive textThe opposite side of the half page contains thenarrative description of the hydraulic fluid as itapplies components or moves valves in the systemFacing this partial page is a hydraulic schematic
which shows the position of valves, checkballsetc., as they function in a specific gear rangeAlso, located at the bottom of each half page is areference to the Complete Hydraulic Circuitsection that follows.
• The Complete Hydraulic Circuits section(beginning on page 67) details the entire hydraulicsystem. This is accomplished by using a foldoutcircuit schematic with a facing page twodimensional foldout drawing of each componentThe circuit schematics and component drawingsdisplay only the fluid passages for that specificoperating range.
• Finally, the Appendix section contains a schematicof the lubrication flow through the transmissiondisassembled view parts lists and transmissionspecifications. This information has been includedto provide the user with convenient referenceinformation published in the appropriate vehicleService Manuals. Since component parts lists andspecifications may change over time, thisinformation should be verified with ServiceManual information.
First time users of this book may find the page layouta little unusual or perhaps confusing. However, witha minimal amount of exposure to this format itsusefulness becomes more obvious. If you areunfamiliar with this publication, the followingguidelines are helpful in understanding the functionalintent for the various page layouts:
• Read the following section, “Understanding the
Graphics” to know how the graphic illustrationsare used, particularly as they relate to themechanical power flow and hydraulic controls(see Understanding the Graphics page 6).
• Unfold the cutaway illustration of the Hydra-matic4L30-E (page 8) and refer to it as you progressthrough each major section. This cutaway providesa quick reference of component location insidethe transmission assembly and their relationshipto other components.
• The Principles of Operation section (beginning onpage 9A) presents information regarding the majorapply components and hydraulic controlcomponents used in this transmission. This sectiondescribes “how” specific components work andinterfaces with the sections that follow.
• The Power Flow section (beginning on page 41)presents the mechanical and hydraulic functionscorresponding to specific gear ranges. This sectionbuilds on the information presented in the
4
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5Figure 1
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UNDERSTANDING THE GRAPHICS
6
Figure 2
The flow of transmission fluid starts in the bottom
pan and is drawn through the filter, main case valvebody, main case, adapter case and into oil pumpassembly. This is a general route for fluid to flowthat is more easily understood by reviewing the il-lustrations provided in Figure 2. However, fluid maypass between these and other components many timesbefore reaching a valve or applying a clutch. For thisreason, the graphics are designed to show the exactlocation where fluid passes through a componentand into other passages for specific gear range op-eration.
To provide a better understanding of fluid flow in theHydra-matic 4L30-E transmission, the componentsinvolved with hydraulic control and fluid flow areillustrated in three major formats. Figure 3 providesan example of these formats which are:
• A three dimensional line drawing of thecomponent for easier part identification.
• A two dimensional line drawing of the componentto indicate fluid passages and orifices.
• A graphic schematic representation that displays
valves, checkballs, orifices and so forth, requiredfor the proper function of transmission in a specificgear range. In the schematic drawings, fluidcircuits are represented by straight lines andorifices are represented by indentations in a circuitAll circuits are labeled and color coded to providereference points between the schematic drawingand the two dimensional line drawing of thecomponents.
• Figure 4 (page 7A) provides an illustration of atypical valve, bushing and valve train componentsA brief description of valve operation is alsoprovided to support the illustration.
• Figure 5 (page 7A) provides a color coded charthat references different fluid pressures used tooperate the hydraulic control systems. A briefdescription of how fluid pressures affect valveoperation is also provided.
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GASKETGASKET
SPACER PLATE
UNRESTRICTEDPASSAGE
ORIFICE IN TRANSFER
PLATE
TWO DIMENSIONAL
CAPILLARYRESTRICTION
THROTTLE SIGNALACCUMULATOR
ASSEMBLY(214-217)
EX
T H R O T T
L E S I G N A L
BOOST PRESSURE REGULATOR
EX L I N E
L I N E
S U C T I O N
C O N V E R T E R I N
R E V E R S E
THROTTLE SIGNAL
C O N V C L C O N T R O L
C O N V I N
R E L E A S E
E X
T O C O
O L E R
A P P L Y
L I N E
E XSOLENOID SIGNAL
PUMPASSEMBLY
(10)
LINE
SUCTION
LINE
S U C T I O N
2-3 SHIFT
E X
E X
E X
4 T H C L F D 1
S E R V O R E L
D 3 2/1-2
D 3 2
EX
SOLENOID(307)
N.O.
EXSOLENOID(303)
N.C.
D 3 2/1-2
1-2 & 3-4 SHIFT
E X
E X
SERVOREL
4TH CL FEED 1
4TH CL FEED 2
1 - 2 R E G
3 R D C L F D
2 N D C L U T C H
D 3 2 / 1 - 2
MANUAL VALVE EX
EX
D 3 2
D 3 2
1 - 2
1 - 2
R 3 2 1
L I N E
R E V E R S E
R 3 2 1 R
E V
P R N 3 2 1D
LOW PRESSURE
E X
E X
1 - 2
1-2 REG
1-2 REG
D 3 2/1-2
PWM SOLENOIDSCREEN (324)
CONTROL 1-2 ACCUM
T H R O T T L E S I G
N A L
1 - 2 A C C
D 3 2/1-2
E X
E X
1-2 ACCUM
E X
D 3 2/1-2
SERVO APPLY
BANDCONTROLSOLENOID
PWM(323)EX
EX
1-2
D 3 2 D 3 2
SERVOREL
FEED LIMIT
EX
EX E X
L I N E
FEED LIMIT
FEED LIMIT
3-4 ACCUM CONTROL
E X
E X
3 - 4 A C C U M
3 - 4 A C C U M
LINE
T H R O T T L E S I G N A L
EX
S O L E N O I D F E E D
S O L E N O I D S I G N A L
CONVERTERCLUTCH
SOLENOID(416)
LINE
FORCE MOTORSCREEN (415)
FORCEMOTOR
SOLENOID(404)
FDLIMIT
T H R O T T L E S I G
T H R O T T L E S I G
E X
2ND CL
REV
OIL PUMP ASSEMBLY (10)
ADAPTER CASE VALVE BODY ASSEMBLY (71)
MAIN CASE VALVE BODY ASSEMBLY (84)
GASKET
(88)
GASKET
(86)
TRANSFER
PLATE
(87)
CONVERTER HOUSING SIDE ADAPTER CASE SIDE
THREE DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION
TWO DIMENSIONAL THREE DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION
TWO DIMENSIONAL THREE DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION
TWO DIMENSIONAL THREE DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION
ADAPTER CASE SIDE
MAIN CASE SIDE
MAIN CASE VALVE BODY SIDE
UNDERSTANDING THE GRAPHICS
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FLUID PRESSURES
SUCTION CONVERTER & LUBE MAINLINE SOLENOID SIGNAL ACCUMULATOR FEED LIMIT THROTTLE SIGNAL
EXHAUST DIRECTION OF FLOW
A B
A B
WITH EQUAL SURFACE AREASON EACH END OF THE VALVE,BUT FLUID PRESSURE "A"BEING GREATER THAN FLUIDPRESSURE "B", THE VALVEWILL MOVE TO THE RIGHT.
WITH THE SAME FLUID PRESSUREACTING ON BOTH SURFACE "A"AND SURFACE "B" THE VALVEWILL MOVE TO THE LEFT. THISIS DUE TO THE LARGER SURFACEAREA OF "A" THAN "B".
UNDERSTANDING THE GRAPHICSTYPICAL BUSHING & VALVE
Figure 4
Figure 5 FOLDOUT 7A
SPRING
RETAINING
PIN
BOREPLUG
VALVE
BUSHING
EXHAUST FROM THE
APPLY COMPONENTUNSEATS THE CHECKBALL, THEREFORE CREATINGA QUICK RELEASE.
TO APPLY
COMPONENT APPLY FLUID SEATS THECHECKBALL FORCING FLUID THROUGH AN ORIFICE IN THE SPACER PLATE, WHICHCREATES A SLOWER APPLY.
WITH SIGNAL FLUID PRESSUREGREATER THAN SPRING ANDSPRING ASSIST FLUID PRESSURE THE VALVE MOVES OVER.
WITH SIGNAL FLUID PRESSUREEQUAL TO OR LESS THANSPRING AND SPRING ASSISTFLUID PRESSURE THE VALVEREMAINS IN CLOSED POSITION.
BUSHING
VALVEBODY
SPACERPLATE
RESTRICTINGORIFICE
CHECKBALL
RETAININGPIN
BOREPLUG
SPRING
VALVE
BUSHING
VALVEBODY
SPACERPLATE
SIGNALFLUID
APPLYFLUID
SPRINGASSISTFLUID
EX
SPACERPLATE
SIGNALFLUID
APPLYFLUID
SPRINGASSISTFLUID
EX
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HYDRA-MATIC 4L30-E
Figure 6
CONVERTERHOUSING
(6)
CONVERTERCLUTCH ASSEMBLY
(1)
TURBINESHAFT(506) OIL PUMP
ASSEMBLY(10)
ADAPTERCASE(20)
OVERDRIVE CLUTCHROLLER ASSEMBLY
(516)
OVERRUNCLUTCH PLATE
ASSEMBLY(520-523)
OVERDRIVE COMPLETECARRIER ASSEMBLY
(525)
REVERSE CLUTCH
PLATE ASSEMBLY(614-616)
2ND CLUTCHPLATE ASSEMBLY
(625-627)
MAINCASE(36)
3RD CLUTCHPLATE ASSEMB
(641-643)
PRINCSPRAGASSEM
(65
CENTERSUPPORT
(30)
MAIN CASEVALVE BODYASSEMBLY
(84)
4TH CLUTCHPLATE ASSEMBLY
(502 & 503)
ADAPTER CASEVALVE BODYASSEMBLY
(71)
SOLENOIDASSEMBLY
(416)
CONVERTERPUMP
ASSEMBLY
STATOR
TURBINEASSEMBLY
PRESSUREPLATE
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HYDRA-MATIC 4L30-ECROSS SECTIONAL DRAWING
This illustration is a typical engineering cross sec-tional drawing of the HYDRA-MATIC 4L30-E trans-mission that has been used sparingly in this publica-tion. Unless an individual is familiar with this typeof drawing, it may be difficult to use when locatingor identifying a component in the transmission. Forthis reason, the three dimensional graphic illustra-
tion on page 8 has been the primary drawing usedthroughout this publication. It also may be used toassist in the interpretation of the engineering draw-ing when locating a component in the transmission.
These illustrations, and others used throughout thebook, use a consistent coloring of the components inorder to provide an easy reference to a specific com-ponent. Colors then remain the same from section tosection, thereby supporting the information containedin this book.
8A
Figure 7
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The Hydra-matic 4L30-E is a fully automatic, fourspeed, front wheel drive transmission. It consists pri-marily of a four-element torque converter, two planetarygear sets, various clutches, an oil pump, and a controlvalve body.
The four-element torque converter contains a pump, aturbine, a pressure plate splined to the turbine, and astator assembly. The torque converter acts as a fluidcoupling to smoothly transmit power from the engineto the transmission. It also hydraulically provides addi-tional torque multiplication when required. The pressureplate, when applied, provides a mechanical “directdrive” coupling of the engine to the transmission.
The two planetary gear sets provide the four forwardgear ratios and reverse. Changing of the gear ratios isfully automatic and is accomplished through the use of various electronic powertrain sensors that provide in-
put signals to the Transmission Control Module (TCM).The TCM interprets these signals to send current to thevarious solenoids inside the transmission.
By using electronics, the TCM controls shift poinshift feel and torque converter clutch apply and lease, to provide proper gear ranges for maximum feconomy and vehicle performance.
Five multiple-disc clutches, one roller clutch, a sp
clutch, and a brake band provide the friction elemerequired to obtaain the various ratios with planetgear sets.
A hydraulic system (the control valve body), pressized by a gear type pump provides the working pressneeded to operate the friction elements and automacontrols.
Several electronic solenoids and sensors in the powtrain work in conjunction with the vehiclTransmission Control Module (TCM), to control vaous shift points, shift feel and converter clutch appand release.
accomplished by depressing the accelerator or by manally selecting a lower gear with the shift selector.
It is not recommended that the transmission be opated in Drive range when pulling heavy loads or dring on extremely hilly terrain. Typically these conditio
put an extra load on the engine, therefore the transmsion should be driven in a lower manual gear selectfor maximum efficiency.
3– Manual Third should be used when driving contions dictate that it is desirable to use only three gratios. These conditions include towing a trailer or dring on hilly terrain as described above. Automatic shing is the same as in Drive range for first, second athird gears except the transmission will not shift iFourth gear.
2– Manual Second adds more performance for c
gested traffic or hilly terrain. It has the same startratio (first gear) as Manual Third but the transmissis prevented from shifting above second gear. ManSecond can be selected at any vehicle speed therefoit is commonly used for acceleration or engine brakas required.
1– Manual First can also be selected at any vehispeed, however if the transmission is in third or fougear it will immediately shift into second gear. Whthe vehicle speed slows to below approximately km/h (37 mph) the transmission will then shift ifirst gear. This is particularly beneficial for mainta
ing maximum engine braking when descending stegrades.
Figure 8
GENERAL DESCRIPTION
EXPLANATION OF GEAR RANGES
P R
N D 3 2 1
The transmission can be operated in any one of theseven different positions shown on the shift quadrant(Figure 8).
P– Park position enables the engine to be started whilepreventing the vehicle from rolling either forward orbackward. For safety reasons, the vehicle’s parkingbrake should be used in addition to the transmission“Park” position. Since the output shaft is mechanically
locked to the case through the parking pawl and park-ing lock wheel, Park position should not be selecteduntil the vehicle has come to a complete stop.
R– Reverse enables the vehicle to be operated in arearward direction.
N – Neutral position enables the engine to start andoperate without driving the vehicle. If necessary, thisposition should be selected to restart the engine whilethe vehicle is moving.
D – Drive range should be used for all normal drivingconditions for maximum efficiency and fuel economy.
Drive range allows the transmission to operate in eachof the four forward gear ratios. When operating in theDrive range, shifting to a lower or higher gear ratio is
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PRINCIPLES OF OPERATION
An automatic transmission is the mechanicalcomponent of a vehicle that transfers power(torque) from the engine to the wheels. Itaccomplishes this task by providing a numberof forward gear ratios that automatically
change as the speed of the vehicle increases.The reason for changing forward gear ratiosis to provide the performance and economyexpected from vehicles manufactured today.On the performance end, a gear ratio thatdevelops a lot of torque (through torquemultiplication) is required in order to initiallystart a vehicle moving. Once the vehicle is inmotion, less torque is required in order tomaintain the vehicle at a certain speed. When
the vehicle has reached a desired speed,economy becomes the important factor andthe transmission will shift into overdrive. Atthis point output speed is greater than inputspeed, and, input torque is greater than outputtorque.
Another important function of the automatictransmission is to allow the engine to be
started and run without transferring torque tothe wheels. This situation occurs wheneverPark (P) or Neutral (N) ranges have beenselected. Also, operating the vehicle in arearward direction is possible whenever
Reverse (R) gear range has been selected(accomplished by the gear sets).
The variety of gear ranges in an automatictransmission are made possible through theinteraction of numerous mechanically,hydraulically and electronically controlledcomponents inside the transmission. At theappropriate time and sequence, thesecomponents are either applied or released andoperate the gear sets at a gear ratio consistentwith the driver’s needs. The following pagesdescribe the theoretical operation of themechanical, hydraulic and electricalcomponents found in the Hydra-matic 4L30-E transmission. When an understanding of these operating principles has been attained,understanding and diagnosis of the entiresystem is easier.
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OVERDRIVESUN GEAR
(519)
OVERDRIVEINTERNAL
GEAR
(528)OVERDRIVE
CARRIERASSEMBLY
(525)
MAJ OR MECHANICAL COMPONENTS
Figure 910
TURBINESHAFT(506)
RAVIGNEAUXPLANETARY
CARRIERASSEMBLY
(653)
BRAKE BANDASSEMBLY
(664)
REACTIONSUN GEAR
(658)
SPLINED TOGETHER
SPLINED TOGETHER
SPLINED TOPARKING
LOCKWHEEL(668)
SPLINED TOSPEEDOWHEEL(672)
OVERRUNCLUTCH
ASSEMBLY (510-524)
ADAPTERCASE(20)
4TH CLUTCH
ASSEMBLY (501-503,530-534)
2ND CLUTCHASSEMBLY (618-629)
MAINCASE(36)
REVERSECLUTCH
ASSEMBLY (608-617)
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TORQUE CONVERTER
Figure 1112
CONVERTER HOUSINGCOVER ASSEMBLY
(A)
PRESSURE PLATEASSEMBLY
(C)
DAMPERASSEMBLY
(D)
TURBINE THRUSTSPACER
(B)
PRESSUREPLATE
SPRING(E)
TURBINEASSEMBLY
(F)
STATORASSEMBLY
(H)
CONVERTER PUMPASSEMBLY
(I)
THRUSTBEARING
ASSEMBLY(G)
THRUSTBEARING
ASSEMBLY(G)
RELEASEFLUID
A
B
C
D
E
F
G
H
I
RELEASEFLUID
APPLYFLUID
APPLYFLUID
TORQUECONVERTERASSEMBLY
(1)
TURBINESHAFT(506)
STATORSHAFT(209)
TCCRELEASED
TCCAPPLIED
TORQUE CONVERTER:The torque converter (1) is the primary component for
transmittal of power between the engine and the trans-
mission. It is bolted to the engine flywheel (also known
as the flexplate) so that it will rotate at engine speed.
The major functions of the torque converter are:• to provide a fluid coupling for a smooth
conversion of torque from the engine to the me-
chanical components of the transmission.
• to multiply torque from the engine which
enables the vehicle to achieve additional
performance when required.
• to mechanically operate the transmission oil
pump (4) through the converter hub.
• to provide a mechanical link, or direct drive, from
the engine to the transmission through the use of
the torque converter clutch (TCC), or pressure
plate (C).
The torque converter assembly consists of
the following five main sub-assemblies:• a converter housing cover assembly
(A) which is bolted to the engine
flywheel and is welded to the
converter pump assembly (I).
• a converter pump assembly (I)
which is the driving member.
• a turbine assembly (F) which is
the driven or output member.
• a stator assembly (H) which is the
reaction member located between the
converter pump and turbine assemblies.
• a pressure plate assembly (C) splined
to the turbine assembly to provide a
mechanical direct drive when appropriate.
CONVERTER PUMP ASSEMBLY ANDTURBINE ASSEMBLY When the engine is running the converter pump as-
sembly acts as a centrifugal pump by picking up fluid
at its center and discharging it at its rim between the
blades (see Figure 12). The force of this fluid then hits
the turbine blades and causes the turbine to rotate. The
turbine shaft (506) is splined to the converter turbine
to provide the input to the transmission. As the engine
and converter pump increase in RPM, so does the
turbine assembly and turbine shaft. However, with the
pressure plate released, turbine speed does not equal
engine speed due to the small amount of slip that
occurs in a fluid coupling.
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Figure 12
Figure 13
TORQUE CONVERTER
STATOR
STATOR ROTATESFREELY
STATOR HELDFLUID FLOW REDIRECTED
CONVERTER ATCOUPLING SPEED
FLUID FLOWFROM TURBINE
CONVERTERMULTIPLYING
FLUID FLOW
TURBINEASSEMBLY
(F)
CONVERTER PUMPASSEMBLY
(I)
STATORASSEMBLY
(H)
To reduce torsional shock during the apply of the pressure plate to the con-
verter cover, a spring loaded damper assembly (D) is used. The damper assem
bly is splined to the turbine assembly and the damper’s pivoting mechanism i
attached to the pressure plate assembly. When the pressure plate applies, the
pivoting mechanism allows the pressure plate to rotate independently of the
damper assembly up to approximately 45 degrees. The cushioning effect of the
damper assembly springs aid in reducing converter clutch apply feel and ir
regular torque pulses from the engine or road surface.
PRESSURE PLATE, DAMPER ANDCONVERTER HOUSING ASSEMBLIESThe pressure plate is splined to the turbine hub and applies (engages) with the
converter cover to provide a mechanical coupling of the engine to the transmis-
sion. When the pressure plate assembly is applied, the small amount of slippage
that occurs through a fluid coupling is eliminated, thereby providing a more
efficient transfer of engine torque to the transmission and drive wheels. The
bottom half of the cutaway view of the torque converter in Figure 11 shows the
pressure plate in the apply position while the top half shows the released
position. Refer to Torque Converter Release and Apply on pages 54 and 55 for
an explanation of hydraulic control of the torque converter clutch.
STATOR ASSEMBLY The stator assembly (or assemblies, see page 14) is
located between the pump assembly and turbine
assembly and is mounted on a roller clutch. The
roller clutch is a type of one-way clutch that pre
vents the stator from rotating in a counterclockwisedirection. The function of the stator is to redirec
fluid returning from the turbine which assists the
engine in turning the converter pump assembly
thereby multiplying torque.
At low vehicle speeds, when greater torque is
needed, fluid from the turbine hits the front side o
the stator blades (converter multiplying torque)
The roller clutch prevents the stator from rotating
in the same direction as the fluid flow, therebyredirecting the fluid and increasing the fluid force
on the pump assembly. Fluid from the converter
pump then has more force to turn the turbine as
sembly and multiply engine torque.
As vehicle speed increases, centrifugal force
changes the direction of fluid leaving the turbine
such that it hits the back side of the stator blades
(converter at coupling speed). When this occurs
the stator overruns the roller clutch and rotates
freely. Fluid is no longer redirected and torque is
no longer multiplied.
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The Apply Components section is designed toexplain the function of the hydraulic andmechanical holding devices used in the Hydra-matic 4L30-E transmission. Some of these applycomponents, such as clutches and a band, arehydraulically “applied” and “released” in order toprovide automatic gear range shifting. Othercomponents, such as a roller clutch or sprag clutch,
often react to a hydraulically “applied” componentby mechanically “holding” or “releasing” anothermember of the transmission. This interactionbetween the hydraulically and mechanicallyapplied components is then explained in detailand supported with a graphic illustration. Inaddition, this section shows the routing of fluidpressure to the individual components and theirinternal functions when it applies or releases.
The sequence in which the components in thissection have been discussed coincides with theirphysical arrangement inside the transmission. Thisorder closely parallels the disassembly sequenceused in the Hydra-matic 4L30-E Unit RepairSection of the appropriate Service Manual. It alsocorrelates with the components shown on theRange Reference Charts that are used throughout
the Power Flow section of this book. Thecorrelation of information between the sections of this book helps the user more clearly understandthe hydraulic and mechanical operating principlesfor this transmission.
APPLY COMPONENTS
Figure 14
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APPLY COMPONENTS
Figure 15
OVERRUNCLUTCH
HOUSING(510)
513 514 515 517 518 519 521 522 523 524520
SOME MODELS
OVERRUN
CLUTCHHOUSING
(510)
OVERRUNCLUTCHPISTON
(513)
RELEASESPRING
(514)
RETAINER(515)
CAM(517)
SNAPRING(518)
SUNGEAR(519)
OVERRUNCLUTCH
STEEL PLATE(521)
OVERRUNCLUTCH
LINED PLATE(522)
OVERRUNCLUTCH
BACKING PLATE(523)
SNAPRING(524)
OVERRUNCLUTCHAPPLYFLUID
APPLIED
RELEASED
EX
OVERRUN CLUTCH CHECKBALL
OVERRUN CLUTCH:The overrun clutch assembly is located in the overrun clutch housing (510)
inside the adapter case (20). The external teeth on the steel clutch plates
(521) are splined to the overrun clutch housing while the internal teeth on
the fiber clutch plates (522) are splined to the overdrive carrier assembly
(525). The overrun clutch is applied as soon as the engine is started and in
all gear ranges except Drive Range - Fourth Gear.
OVERRUN CLUTCH APPLY:To apply the overrun clutch, overrun clutch fluid is fed through
the oil pump hub, into the turbine shaft (506) and to the inner hub
of the overrun clutch housing. Feed holes in the inner hub allow
fluid to enter the housing behind the overrun clutch piston (513).
Overrun clutch fluid pressure seats the overrun clutch checkball
(located in the housing) and moves the piston to compress the
waved release spring (514) which cushions the clutch apply. As
fluid pressure increases, the piston compresses the steel and fiber
clutch plates together until they are held against the overrun
clutch backing plate (523). The increase in fluid pressure forces
any air in the overrun clutch fluid circuit to exhaust past thecheckball, before it fully seats, to prevent excess cushion during
the clutch apply.
When fully applied, the steel plates (521) and fiber plates (522)
are locked together, thereby holding the overrun clutch housing
and overdrive carrier assembly together. This forces the housing,
overdrive sun gear (519) which is splined to the housing’s inner
hub, and carrier to rotate at the same speed.
OVERRUN CLUTCH RELEASE:To release the overrun clutch, overrun clutch fluid exhausts from
the housing and back through the turbine shaft and oil pump hub,
thereby decreasing fluid pressure at the overrun clutch piston
(513). Without fluid pressure, spring force from the waved re-
lease spring (514) moves the overrun clutch piston away from
clutch pack. This disengages the steel and fiber clutch plates fromthe backing plate (523) and disconnects the overrun clutch hous-
ing (510) from the overdrive carrier (525).
During the exhaust of overrun clutch fluid, the overrun clutchcheckball unseats (see illustration). Centrifugal force, resulting
from the overrun clutch housing rotating, forces residual overrun
clutch fluid to the outside of the piston housing and past the
unseated checkball. If this fluid did not completely exhaust from
behind the piston there could be enough pressure for a partial
apply, or drag, of the overrun clutch plates.
Note: Some models use a waved plate (520) to help control the
overrun clutch apply feel.
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APPLY COMPONENTS
R O T A
T I NG
H E L
D
OVERDRIVECARRIER
ASSEMBLY(525)
OVERRUNCLUTCHPLATE
(521-522)
OVERDRIVEINTERNAL
GEAR(528)
(OUTER RACE)OVERRUN CLUTCH HOUSINGAND SUN GEAR (INNER CAM)
EXAMPLE "B"OVERDRIVE
OVERDRIVEROLLER CLUTCH
(516)OVERRUNING
R O T A
T I NG
R O T A
T I N G
OVERDRIVECARRIER
ASSEMBLY(525)
OVERRUNCLUTCHPLATE
(521-522)
OVERDRIVEINTERNAL
GEAR(528)
(OUTER RACE)OVERRUN CLUTCH HOUSINGAND SUN GEAR (INNER CAM)
EXAMPLE "A"DIRECT DRIVE
OVERDRIVEROLLER CLUTCH
(516)HOLDING
OIL SEALRING(508)
OVERDRIVEROLLERCLUTCH
(516)
TURBINESHAFT(506)
OVERDRIVECARRIER
ASSEMBLY(525)
SNAPRING(526)
OVERRUNCLUTCHAPPLYFLUID
LUBEPASSAGE
508 525 526
506516 504 505
OVERDRIVE ROLLER CLUTCH:The overdrive roller clutch assembly (516) is located between the overdrive
carrier assembly (525) and overrun clutch housing (510). The outer race of
the roller clutch is pressed into the overdrive carrier while the roller clutch
inner cam (517) is splined to the inner hub of the overrun clutch housing.
The overdrive roller clutch is a type of one-way clutch that prevents the
overrun clutch housing from rotating clockwise faster than the overdrivecarrier. This assists the overrun clutch in holding the overrun clutch hous-
ing and overdrive carrier together. The overdrive roller clutch is holding,
and effective, during acceleration in all gear range except Drive Range -
Fourth Gear, the same as the overrun clutch.
ROLLER CLUTCH HOLDING: (EXAMPLE "A") DIRECT DRIVEWhen the 4th clutch is released the overrun clutch housing is free to rotate.
The overdrive carrier pinion gears are in mesh with both the overdrive sun
gear (519), which is splined to the inner hub of the overrun clutch housing,
and the overdrive internal gear (528). Power from the engine drives the
overdrive carrier clockwise. Vehicle load holding the overdrive internal
gear causes the pinion gears to attempt to rotate counterclockwise on their
pins around the internal gear as the travel clockwise with the carrier assem-
bly. Therefore, the pinion gears attempt to drive the sun gear clockwise,
faster than the carrier assembly is rotating. However, this causes the rollers
to ‘move up the ramp’ on the inner cam (517) and wedge between the innercam and outer race, thereby locking the overrun clutch housing (510) and
overdrive carrier together.
With the sun gear and overdrive carrier rotating at the same speed, the
pinion gears do not rotate on their pins but act as wedges and drive the
overdrive internal gear. This creates a 1:1 gear ratio through the overdrive
planetary gear set. Remember that, as explained above, the roller clutch is
assisting the overrun clutch which is also applied and holding the carrier
and overrun clutch housing together.
ROLLER CLUTCH RELEASED: (EXAMPLE "B") OVERDRIVEThe roller clutch releases when the overdrive carrier rotates clockwise
faster than the overrun clutch housing. This causes the rollers to ‘move
down the ramp’ on the inner cam (517) and rotate freely between the inner
cam and outer race. This action occurs in Fourth gear when the overrun
clutch is released and the 4th clutch is applied to hold the overrun clutch
housing (510) and overdrive sun gear (519) stationary to the adapter case.As torque from the engine drives the carrier clockwise, the roller clutch
outer race in the carrier overruns the roller clutch. The pinion gears rotate
clockwise on their pins and walk around the stationary sun gear, thereby
driving the overdrive internal gear (528) in a Fourth gear overdrive gear
ratio of approximately .73:1.
Coast Conditions:When the throttle is released and the vehicle is decelerating, power from
vehicle speed drives the transmission’s output shaft and gear sets faster
than engine torque is driving. In gear ranges when the overrun clutch is
applied and engine compression braking slows the vehicle during coast
conditions, the overdrive roller clutch is not holding. However, the over-
drive carrier does not overrun the roller clutch because the overrun clutch
holds the carrier and overrun clutch housing together.
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APPLY COMPONENTS
18
ADAPTERCASE(20)
4TH CLUTCHAPPLYFLUID
4TH CLUTCHRETAINER
(501)
4TH CLUTCHSTEEL PLATE
(502)
4TH CLUTCHLINED PLATEASSEMBLY
(503)
SNAPRING(530)
RETAINER& SPRINGASSEMBLY
(531)
4TH CLUTCHPISTON
(532)
SEAL(INNER)
(533)
SEAL(OUTER)
(534)
ADAPTERCASE(20)
532 533 534531530501 502 503
4TH CLUTCH:The 4th clutch assembly is located in the adapter case. The external teeth on the
steel clutch plates (502) are splined to the adapter case while the internal teeth on
the fiber clutch plates (503) are splined to the outside of the overrun clutch
housing (510). The 4th clutch is only applied in Drive Range - Fourth Gear to
provide an overdrive gear ratio through the overdrive planetary gear set.
4TH CLUTCH APPLY:To apply the 4th clutch, 4th clutch fluid is fed
from the center support (30) into the adapter
case behind the 4th clutch piston (532). 4th
clutch fluid pressure moves the piston to com-
press the retainer and spring assembly (531)
which cushions the clutch apply. As fluid pres-
sure increases, the piston compresses the steel
and fiber clutch plates until they are held against
the 4th clutch retainer (501). The 4th clutchretainer is splined to the adapter case and held
in place by the oil pump assembly (10). The
retainer functions as a backing plate for the
clutch pack.
When fully applied, the steel and fiber clutch
plates are locked together and held stationary to
the adapter case. The internal teeth on the fiber
clutch plates (503) hold the overrun clutch hous-
ing (510) stationary. This prevents the overdrive
sun gear (519), which is splined to the overrun
clutch housing’s inner hub, from rotating.
4TH CLUTCH RELEASE:To release the 4th clutch, 4th clutch fluid ex-
haust from the adapter case and back throughthe center support (30), thereby decreasing fluid
pressure at the 4th clutch piston (532). Without
fluid pressure, spring force from the piston
spring assembly (531) moves the 4th clutch pis-
ton away from the clutch pack. This disengages
the steel and fiber clutch plates from the 4th
clutch retainer (501) and allows the overrun
clutch housing and overdrive sun gear to rotate
freely.
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APPLY COMPONENTS
MAINCASE
(36)
30 31 12 32
617616614 615613612611610608 609
SEAL(OUTER)
(609)
SEAL(INNER)
(608)
REVERSECLUTCHPISTON
(610)
PISTONCLUTCHSPRING
(611)
SPRINGSEAT(612)
RETAININGRING(613)
REVERSE CLUTCHWAVED PLATE
(614)
REVERSE CLUTCHSTEEL PLATE
(615)
REVERSE CLUTCHLINED PLATE
(616)
REVERSE CLUTCHPRESSURE/SELECTIVE
PLATE(617)
OILSEAL
RINGS(32)
CENTERSUPPORT
ASSEMBLY(30)
MAINCASE(36)
REVERSE CLUTCH:The reverse clutch is located in the main transmission case (31) directly
behind the center support (604). The external teeth on the steel clutch
plates (615) are splined to the main case while the internal teeth on the
fiber clutch plates (616) are splined to the outside of the 2nd clutch drum
(618). The reverse clutch is only applied when the gear selector lever is in
the Reverse (R) position.
REVERSE CLUTCH APPLIED:To apply the reverse clutch, reverse clutch fluid is fed
from the center support into the cavity behind the re-
verse clutch piston (610). Reverse clutch fluid pressure
moves the piston to compress the piston spring assem-
bly (611) which cushions the clutch apply. As fluid pres-
sure increases, the piston compresses the steel and fiber
clutch plates together until they are held against the
selective reverse clutch pressure plate (617). The pres-
sure plate, which is selective for assembly purposes, is
held stationary by the main case and functions as a
backing plate for the clutch pack. Also included in the
reverse clutch assembly is a steel waved plate (614) that,
in addition to the spring assembly (611), helps cushion
the reverse clutch apply.
When fully applied, the steel clutch plates (615), fiber
clutch plates (616) and waved plate (614) are locked
together and held stationary to the main case. The inter-
nal teeth on the fiber clutch plates hold the 2nd clutchdrum (618) and ring gear (630) stationary.
REVERSE CLUTCH RELEASE:To release the reverse clutch, reverse clutch fluid pres-
sure exhausts from the reverse clutch piston (610) and
center support. Without fluid pressure, spring force from
the piston spring assembly (611) and waved plate (614)
moves the reverse clutch piston away from the clutch
pack. This disengages the steel plates, fiber plates and
waved plate from the pressure plate (617) and allows the
2nd clutch drum and ring gear to rotate freely.
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APPLY COMPONENTS
Figure 1920
2ND CLUTCHDRUM ASSEMBLY
(618)
620 621 622 611
623 613 625 626 627 628 629 629630
SEAL
(INNER)(620)
SEAL
(OUTER)(621)
2ND
CLUTCHPISTON
(622)
PISTON
CLUTCHSPRING(611)
SPRING
SEAT(623)
RETAINING
RING(624)
2NDCLUTCHWAVEDPLATE(625)
2NDCLUTCHSTEEL
PLATE(626)
2NDCLUTCHLINED
PLATE(627)
RETAINING
RING(629)
RING
GEAR(630)
2NDCLUTCHSPACER
(628)
2ND CLUTCHAPPLYFLUID
2ND
CLUTCHDRUMASSEMBLY
(618)
APPLIED
EX
RELEASED
2ND CLUTCH CHECKBALLAlso included in the 2nd clutch assembly is a
steel waved plate (625) that, in addition to the
spring assembly (611), helps cushion the 2nd
clutch apply. When fully applied, the steel clutch
plates (626), fiber clutch plates (627) and waved
plate are locked together, thereby holding the 2nd
clutch drum and 3rd clutch drum together. This
forces both drums and the ring gear (630), which
is splined to the 2nd clutch drum, to rotate at the
same speed.
2ND CLUTCH RELEASE:To release the 2nd clutch, 2nd clutch fluid ex-
hausts from the 2nd clutch drum (618) and back
through the intermediate shaft and center support
(604), thereby decreasing fluid pressure at the
2nd clutch piston (622). Without fluid pressure,
spring force from the piston spring assembly
(611) and waved plate (625) moves the 2nd clutch
piston away from the clutch pack. This disen-
gages the steel plates, fiber plates and waved plate
from the spacer ring (628) and disconnects the
2nd and 3rd clutch drums. During the exhaust of
2nd clutch fluid, the 2nd clutch checkball unseats
(see illustrat ion). Centrifugal force, resulting
from the 2nd clutch drum rotating, forces residual2nd clutch fluid to the outside of the piston hous-
ing and past the unseated checkball. If this fluid
did not completely exhaust from behind the pis-
ton there could be enough pressure for a partial
apply, or drag, of the 2nd clutch plates.
2ND CLUTCH:The 2nd clutch assembly is located in the 2nd clutch drum (618) inside the main transmission case (31).
The external teeth on the steel clutch plates (626) are splined to the 2nd clutch drum while the internal teeth
on the fiber clutch plates (627) are splined to the 3rd clutch drum assembly (634). The 2nd clutch is applied
when the transmission is in Second, Third and Fourth gears.
2ND CLUTCH APPLY:To apply the 2nd clutch, 2nd clutch fluid is fed through the center support (604), into the intermediate shaft
which is connected to the 3rd clutch drum, and to the inner hub of the 2nd clutch drum. Feed holes in the
inner hub allow fluid to enter the drum behind the 2nd clutch piston (622). 2nd clutch fluid pressure seats
the 2nd clutch checkball (located in the drum) and moves the piston to compress the piston spring assembly
(611) which cushions the clutch apply. As fluid pressure increases, the piston compresses the steel and fiberclutch plates together until they are held against the 2nd clutch spacer (628). The spacer is splined to the
2nd clutch drum and held in place by the retainer ring (629). The spacer functions as a backing plate for the
clutch pack. The increase in fluid pressure forces any air in the 2nd clutch fluid circuit to exhaust past the
2nd clutch checkball, before it fully seats, to prevent excess cushion during the clutch apply.
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APPLY COMPONENTS
3RD CLUTCHDRUM ASSEMBLY
(634)
3RDCLUTCHPISTON
(638)
3RDCLUTCHDRUM
ASSEMBLY(634)
SEAL(INNER)
(635)
SEAL(OUTER)
(637)
PISTONCLUTCHSPRING
(611)
SPRINGSEAT(639)
RETAININGRING(640)
3RDCLUTCHSPRING
CUSHIONPLATE(641)
3RDCLUTCHSTEELPLATE(642)
3RDCLUTCHLINEDPLATE(643)
SPRAGRACE
ASSEMBLY(647)
SPRAG RACERETAINING
RING(648)
3RDCLUTCHAPPLYFLUID
LUBEPASSAGE
LUBEPASSAGE
APPLIED
EX
RELEASED
3RD CLUTCH CHECKBALL
648647643642641640639611638637635
3RD CLUTCH:The 3rd clutch assembly is located in the 3rd clutch drum (634) inside the
main transmission case (31). The external teeth on the steel clutch plates
(642) are splined to the 3rd clutch drum while the internal teeth on the fiber
clutch plates (643) are splined to the input sun gear assembly (646). The
3rd clutch is applied when the transmission is in Drive Range - Third and
Fourth gears. The 3rd clutch is also applied in First gear when the transmis-
sion is operating in Manual Second and Manual First to provide engine
compression braking.
3RD CLUTCH APPLY:To apply the 3rd clutch, 3rd clutch fluid is fed through the
center support (604), into the intermediate shaft which is
connected to the 3rd clutch drum, and to the inner hub of
the 3rd clutch drum. Feed holes in the inner hub allow fluid
to enter the drum behind the 3rd clutch piston (638). 3rd
clutch fluid pressure seats the 3rd clutch checkball (located
in the drum) and moves the piston to compress the piston
spring assembly (611) which cushions the clutch apply. As
fluid pressure increases, the piston compresses the steel and
fiber clutch plates together until they are held against the
sprag race assembly (647). The sprag race assembly is
splined to the 3rd clutch drum and held in place by the
sprag retainer ring (648). The sprag race functions as abacking plate for the clutch pack. The increase in fluid
pressure forces any air in the 3rd clutch fluid circuit to
exhaust past the 3rd clutch checkball, before it fully seats,
to prevent excess cushion during the clutch apply.
Also included in the 3rd clutch assembly is a steel spring
cushion plate (641) that, in addition to the spring assembly
(611), helps cushion the 3rd clutch apply. When fully ap-
plied, the steel clutch plates (642), fiber clutch plates (643)
and spring plate (641) are locked together, thereby
holding the 3rd clutch drum and input sun gear
assembly (646) together. This forces the 3rd clutch
drum and input sun gear to rotate at the same speed.
3RD CLUTCH RELEASE:
To release the 3rd clutch, 3rd clutch fluid exhaustsfrom the 3rd clutch drum (634) and back through the
intermediate shaft and center support (604), thereby
decreasing fluid pressure at the 3rd clutch piston (638).
Without fluid pressure, spring force from the piston spring
assembly (611) and spring plate (641) moves the 3rd clutch
piston away from the clutch pack. This disengages the steel
plates, fiber plates and spring plate from the sprag race
assembly (647) and disconnects the 3rd clutch drum from
the input sun gear assembly.
During the exhaust of 3rd clutch fluid, the 3rd clutch
checkball unseats (see illustration). Centrifugal force, re-
sulting from the 3rd clutch drum rotating, forces residual
3rd clutch fluid to the outside of the piston housing and pastthe unseated checkball. If this fluid did not completely ex-
haust from behind the piston there could be enough pres-
sure for a partial apply, or drag, of the 3rd clutch plates.
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INPUTSUN GEARASSEMBLY
(646)
22
APPLY COMPONENTS
Figure 21
650 649649
INPUTSUN GEARASSEMBLY
(646)
RETAININGRING(649)
SPRAGCAGE
ASSEMBLY(650)
LUBEPASSAGE
(INNER RACE)INPUTSUNGEAR(646)
SPRAGCAGE
ASSEMBLY(650)
SPRAG CLUTCHHOLDING/DRIVING(OUTER RACE)
SPRAGRACE
ASSEMBLY(647)
(B)
(A)
(INNER RACE)INPUTSUNGEAR(646)
SPRAGCAGE
ASSEMBLY(650)
SPRAG CLUTCHOVERRUNNING(OUTER RACE)
SPRAGRACE
ASSEMBLY(647)
SPRAG CLUTCH:The sprag clutch assembly (650) is located between the input sun gear assembly (646) and sprag raceassembly (647). The input sun gear assembly functions as the inner sprag race and is splined to the
short pinions in the Ravigneaux planetary carrier (653). The sprag race assembly functions as the
outer sprag race and is splined to the 3rd clutch drum (634). The sprag clutch is a type of one-way
clutch that prevents the 3rd clutch drum from rotating clockwise faster than the input sun gear.
Therefore, when the sprag clutch is holding it allows the 3rd clutch drum to drive the input sun gear.
SPRAG CLUTCH HOLDING:In Park, Reverse, Neutral and First gears power flow drives the 3rd
clutch drum clockwise such that the sprag outer race pivots the spragstoward their long diagonals. The length of the sprag’s long diagonal
(distance A) is greater than the distance between the inner and outer
races. This causes the sprags to ‘lock’ between the inner and outer races,
thereby allowing the 3rd clutch drum to drive the input sun gear assem-
bly. The sun gear then transfers the power flow to the Ravigneaux
carrier and output shaft.
The sprag clutch is also holding in Third and Fourth gears, and First
gear in Manual First and Manual Second. However, in these gear ranges
the 3rd clutch is applied and connects the 3rd clutch drum and input sun
gear assembly. In this situation the sprag clutch assists the 3rd clutch in
driving the input sun gear. This locks the sprag clutch at all times,
during both acceleration and deceleration to provide engine compres-
sion braking.
Note: Refer to the Power Flow section for a complete description of power flow and operation of the sprag clutch during each gear range.
SPRAG CLUTCH RELEASED:The sprag clutch releases when the sprags pivot toward their short
diagonals. The length of the short diagonal (distance B) is less than the
distance between the inner and outer sprag races. This action occurs
when power flow drives the input sun gear clockwise faster than the 3rd
clutch drum, thereby allowing the input sun gear and inner race (646) to
overrun the sprag clutch. During acceleration the sprag clutch is only
overrun when the transmission is in Second gear.
Coast Conditions:The sprag clutch is also overrun during coast conditions, or decelera-
tion, in Reverse, Drive Range - First Gear and Manual Third - First
Gear. This is when power from vehicle speed drives the input sun gear
clockwise faster than engine torque drives the 3rd clutch drum (with the3rd clutch released). In this situation, the sprag clutch inner race on theinput sun gear assembly overruns the sprags, thereby allowing the ve-
hicle to coast freely.
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APPLY COMPONENTS
S E R V O
A P P
L Y
S E R V O R
E L E A S E
SERVO PISTONASSEMBLY
(94-103)
103
102
101
100
99
98
97
96
95
94
93
92
91
90
BRAKE BANDASSEMBLY
(664)
ANCHORPINS
RETURNSPRING
(103)
APPLYROD(102)
ADJ USTSLEEVE
(101)
CUSHIONSPRINGSEAT(100)
CUSHION
SPRING(99)
RINGSEAL(98)
SERVOPISTON
(97)
SERVOPISTONSCREW
(96)
SERVOSCREW
NUT(95)
SERVOCOVER
(91)
MAINCASE(36)
MAIN CASEBOTTOM PAN
(57)
SERVO ASSEMBLY AND BRAKE BAND:The servo assembly, located in the bottom rear of the main transmission case (36), functions to apply the
brake band (664) and act as an accumulator to cushion the 3rd clutch apply. The brake band is applied when
the transmission is in First and Second gears. The brake band is held stationary in the main case and wraps
around the reaction sun drum (659). When compressed by the servo assembly the band holds the reaction
drum and reaction sun gear (658) stationary to the main case.
BRAKE BAND APPLY:To apply the servo assembly and brake band, servo apply fluid is fed between the servo cover (91) and servo
piston (97). Servo apply fluid pressure forces the piston to compress both the servo cushion (99) and servo
return (103) springs. This action moves the servo apply rod (102) toward the band. The apply rod compressesthe brake band around the reaction sun drum and holds both the drum and reaction sun gear stationary to the
main case. During apply, the spring forces (servo cushion and servo return) acting against servo apply fluid
pressure help control the apply feel of the brake band.
BRAKE BAND RELEASE:The servo assembly and brake band are held in the release position by the spring forces in Park, Neutral and
Reverse when servo apply fluid pressure is exhausted. In Third and Fourth gears they are held in the release
position by servo release fluid pressure assisting the spring forces. Servo release fluid pressure is fed between
the main case and servo piston. This fluid pressure assists the spring forces to move the servo piston and apply
rod against servo apply fluid pressure and away from the brake band. Therefore, the brake band releases and
the reaction drum and reaction sun gear are allowed to rotate freely.
3RD CLUTCH ACCUMULATION:The servo assembly is also used as an accumulator for 3rd clutch apply. Servo release fluid pressure also
feeds the 3rd clutch fluid circuit to apply the 3rd clutch. Therefore, as servo release fluid pressure moves the
servo piston against servo apply fluid pressure, some of the initial fluid pressure that applies the 3rd clutch isabsorbed. This helps cushion the 3rd clutch apply. Refer to page 32A for a more detailed description of
accumulator function.
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Torque:When engine torque is transferred through a gear set the output torque from the
gear set can either increase, decrease, or remain the same. The output torque
achieved depends on:
(1) which member of the gear set provides the input torque to the gear set,
(2) which member of the gear set (if any) is held stationary,
and,
(3) which member of the gear set provides the output torque.
If output torque is greater than input torque the gear set is operating in reduction
(First, Second and Reverse gears). If output torque is less than input torque then
the gear set is operating in overdrive (Fourth gear). When output torque equals
input torque the gear set is operating in direct drive (Third gear) and all gear set
components are rotating at the same speed.
Torque vs. SpeedOne transmission operating condition directly affected by input and output
torque through the gear sets is the relationship of torque with output speed. As
the transmission shifts from First to Second to Third to Fourth gear, the overall
output torque to the wheels decreases as the speed of the vehicle increases (with
input speed and input torque held constant). Higher output torque is needed
with low vehicle speed, First and Second gears, to provide the power to move
the vehicle from a standstill. However, once the vehicle is moving and the speed
of the vehicle increases, Third and Fourth gears, less output torque is required to
maintain that speed.
REDUCTIONIncreasing the output torque is known as operating in reduction because there
is a decrease in the speed of the output member proportional to the increase in
output torque. Therefore, with a constant input speed, the output torque
increases when the transmission is in a lower gear, or higher gear ratio.
PLANETARY GEAR SETSPlanetary gear sets are used in the Hydra-matic 4L30-E transmission as the
primary method of multiplying the torque, or twisting force, of the engine
(known as reduction). A planetary gear set is also used to reverse the direction
of input torque, function as a coupling for direct drive, and provide an overdrive
gear ratio.
Planetary gears are so named because of their physical arrangement. All
planetary gear sets contain at least three main components:
• a sun gear at the center of the gear set,
• a carrier assembly with planet pinion gears that rotate around the sun gear
and,
• an internal ring gear that encompasses the entire gear set.
This arrangement provides both strength and efficiency and also evenly
distributes the energy forces flowing through the gear set. Another benefit of
planetary gears is that gear clash (a common occurrence in manual
transmissions) is eliminated because the gear teeth are always in mesh.
The Hydra-matic 4L30-E transmission consists of two planetary gear sets, the
overdrive and Ravigneaux gear sets. The graphics in Figure 23 show both of
these gear sets and their respective components. Figure 24 graphically explains
how the planetary gear sets are used in combination to achieve each of the
transmissions five different gear ratios.
Ravigneaux Planetary Gear Set:The Ravigneaux planetary gear set is unique in that it resembles a combination
of two gear sets. This gear set consists of two sets of pinion gears (long andshort) in one planetary carrier (653), two sun gears - input (646) and reaction
(658), and one internal ring gear (630). The short pinion gears are in constant
mesh with both the input sun gear and the long pinion gears. The long pinion
gears are also in constant mesh with the internal ring gear (630). Also, the
output shaft is connected to the Ravigneaux planetary carrier assembly (653).
24 Figure 23
PLANETARY GEAR SETS
INPUTSUN GEARASSEMBLY
(646)
RAVIGNEAUXPLANETARY
CARRIERASSEMBLY
(653)
OVERDRIVESUN GEAR
(519)
OVERDRIVEINTERNAL
GEAR(528)
OVERDRIVECARRIER
ASSEMBLY(525)
ADAPTERCASE(20)
OVERRUNCLUTCH
HOUSING(510)
2ND CLUTCHDRUM ASSEMBLY
(618)
MAINCASE(36)
REACTIONSUN GEAR
(658)
REACTIONSUN DRUM
(659)
OVERDRIVESUN GEAR
(519)
OVERDRIVEINTERNAL
GEAR(528)
OVERDRIVECARRIER
ASSEMBLY(525)
INPUTSUN GEARASSEMBLY
(646)
RAVIGNEAUXPLANETARY
CARRIERASSEMBLY
(653)
REACTIONSUN GEAR
(658)
RINGGEAR(630)
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Direct drive occurs in Third gear when input torque to the Ravigneaux gear set
is provided by both the input sun gear (646) and ring gear (630). This wedges
the short and long pinion gears together, preventing them from rotating on their
pins, and causes them to rotate with the input sun gear and ring gear at the same
speed. Therefore, the Ravigneaux carrier and output shaft assembly (653) are
also driven at the same speed for a 1:1 direct drive gear ratio. This combines
with the 1:1 gear ratio through the overdrive gear set for a direct drive 1:1 gear
ratio through the entire transmission.
OVERDRIVEOperating the transmission in Overdrive allows the output speed of the
transmission to be greater than the input speed from the engine. This mode ofoperation allows the vehicle to maintain a given road speed with reduced engine
speed for increased fuel economy.
Overdrive is achieved through the overdrive gear set and only occurs in Drive
Range - Fourth Gear. The 4th clutch holds theoverrun clutch housing (510) and
overdrive sun gear (519) stationary to the main transmission case. Therefore
when input torque drives the overdrive carrier clockwise, the overdrive carrier
pinion gears walk clockwise around the stationary sun gear. These pinion gears
then drive the overdrive internal gear (528) clockwise in an overdrive gear ratio
of approximately .73:1. Power flow from the overdrive internal gear to the
output shaft is identical to Third gear, a direct drive 1:1 gear ratio, thereby
providing an overall transmission gear ratio of approximately .73:1.
REVERSEThe Ravigneaux planetary gear set reverses the direction of power flow rotation
when the reverse clutch is applied. In Reverse, input torque to the Ravigneaux
gear set is provided by the input sun gear (646) in a clockwise direction and thering gear (630) is held stationary. The input sun gear drives the short pinion
gears counterclockwise. With the ring gear held, the long pinion gears trave
counterclockwise around the ring gear as they are driven clockwise on their pins
by the short pinion gears. This action drives the Ravigneaux carrier and output
shaft in a counterclockwise (reverse) direction in a reduction gear ratio of
approximately 2.00:1.
Reduction occurs in First, Second and Reverse gears through the Ravigneaux
gear set. In each of these gears, power flow through the overdrive planetary gear
set is a 1:1 direct drive gear ratio. The overdrive carrier assembly provides the
input torque to the overdrive gear set. The overdrive sun gear (519) is splined to
the inner hub of the overrun clutch housing (510). Both of these components are
held to the overdrive carrier assembly (525) by the overrun clutch and overdrive
roller clutch. With the sun gear and carrier rotating at the same speed, the pinion
gears do not rotate on their pins but act as wedges to drive the overdrive internal
gear (528). Therefore, the entire overdrive planetary gear set rotates at the same
speed for a 1:1 gear ratio input to the Ravigneaux gear set.
In First gear, torque input to the Ravigneaux gear set is provided by the inputsun gear (646) in a clockwise direction. The input sun gear drives the short
pinion gears in the Ravigneaux carrier counterclockwise. The short pinion gears
then drive the long pinion gears in the Ravigneaux carrier in a clockwise
direction. The brake band is applied in First and Second gears and holds the
reaction sun gear (658) and reaction sun drum (659) stationary. The long pinion
gears walk clockwise around the stat ionary reaction sun gear. This action drives
the Ravigneaux carrier and output shaft assembly in an reduction gear ratio of
approximately 2.40:1.
In Second gear, the torque input to the Ravigneaux gear set is provided by the
ring gear (630) in a clockwise direction. The ring gear drives the long pinion
gears clockwise. The long pinion gears walk around the stationary reaction sun
gear (658) which is still held by the band. This action drives the Ravigneaux
carrier and output shaft assembly in a reduction gear ratio of approximately
1.48:1.
DIRECT DRIVEDirect drive in a planetary gear set is obtained when any two members of the gear
set rotate in the same direction at the same speed. This forces the third member of
the gear set to rotate at the same speed. Therefore, in direct drive the output speed
of the transmission is the same as the input speed from the converter turbine.
Output speed will equal engine speed when the torque converter clutch is applied
(see Torque Converter - page 12).
PLANETARY GEAR SETS
Figure 24
REVERSE FIRST THIRD FOURTHSECOND
OVERDRIVE PLANETARY GEARSET(DIRECT DRIVE)
OVERDRIVE PLANETARY GEARSET(OVERDRIVE)
HELD
HELD
HELD HELD
(REDUCTION) (REDUCTION) (REDUCTION) (DIRECT DRIVE)
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HYDRAULIC CONTROL COMPONENTS
Figure 25
209 (10)
201
202
5
6
8
9
PUMPASSEMBLY
(10)
LINE
SUCTION
BOTTOM PAN(74)
FILTER(79)
DRIVENGEAR(202)
DRIVEGEAR(201)
INTAKE
OUTLET
CRESCENT
OIL PUMP ASSEMBLY The oil pump assembly contains a positive displacement internal-exter-
nal gear type pump located in the oil pump body (209). This spur geartype pump consists of a drive gear (201) that has gear teeth in constantmesh with the teeth on one side of the pump driven gear (202). Also, thenotch on the inside of the drive gear is keyed to the torque converterpump hub. Therefore, whenever the engine is cranking, or running, theconverter pump hub drives the pump drive gear at engine speed. Thedrive gear then drives the driven gear at engine speed.
On the opposite side of the mesh point between the drive and drivengears the pump gears are separated by the crescent section of the pumpbody (209). As the gears rotate toward the crescent, the volume betweenthe gear teeth increases and fluid volume is positively displaced, therebycreating a vacuum at the pump intake port. This vacuum allows thehigher atmospheric pressure acting on the fluid in the main case bottompan (74) to force fluid through the filter assembly (79) and into thesuction side of the oil pump.
Through the rotation of the gears the gear teeth carry the fluid past thecrescent to the pressure side of the oil pump. Past the crescent the gearteeth begin to mesh again and the volume between the gear teeth de-creases. Decreasing this volume pressurizes and forces the fluid throughthe pump outlet and into the line fluid circuit. This fluid is directed tothe pressure regulator valve where the fluid pressure is regulated tomaintain the required supply and pressure for the various hydrauliccircuits and apply components throughout the transmission.
As engine speed (RPM) increases, the volume of fluid being suppliedby the oil pump also increases because of the faster rotation of thepump gears. At a specified calibrated pressure (which varies with trans-mission model) the pressure regulator valve allows excess fluid to re-turn to the suction side of the pump gears (see pressure regulation onpage 28). The result is a control of the pump’s delivery rate of fluid tothe hydraulic system.
HYDRAULIC CONTROL COMPONENTSThe previous sections of this book described the operation of the majormechanical components used in the Hydra-matic 4L30-E. This sectionprovides a detailed description of the individual components used in thehydraulic system. These hydraulic control components apply and re-lease the various clutches, band and accumulators that provide for theautomatic shifting of the transmission.
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HYDRAULIC CONTROL COMPONENTS
Figure 26
EX
L I N E L
I N E
S U C T I O N
C O N V I N
R E V E R S E
T H R O T T L E S I G N A L
PUMPASSEMBLY
(10)
LINE
S U C T I O N
FEED LIMIT
E X
L I N E
T H R O T T L E S I G
S U C T I O N
EXAMPLE "A": MINIMUM
BOOST PRESSURE REGULATOR
FORCEMOTOR
SOLENOID(404)
BOOST PRESSURE REGULATOR
EX
L I N E L
I N E
S U C T I O N
C O N V I N
R E V E R S E
T H R O T T L E S I G N A L
PUMPASSEMBLY
(10)
LINE
S U C T I O N
FORCEMOTOR
SOLENOID(404)
FEED LIMIT
E X
L I N E
T H R O T T L E S I G
S U C T I O N
EXAMPLE "B": MAXIMUM
PRESSURE REGULATIONTo pressurize pump output there needs to be a restriction in the linepressure fluid circuit. The main restricting component that controls linepressure is the pressure regulator valve (208) which is located in the oilpump assembly (209). Line fluid from the pump is directed to themiddle of the pressure regulator valve and is also orificed to one end of the valve. The larger surface area at the end of the valve allows the forcefrom line pressure to move the valve against throttle signal fluid pres-sure.
EXAMPLE A: MINIMUM LINE PRESSURE (minimum throttle)As the pump continually supplies fluid and line pressure builds, thepressure regulator valve moves against the force of the pressure regula-tor valve spring (207) and throttle signal fluid pressure. This opens theline pressure circuit at the middle of the valve to enter the ‘converter in’fluid circuit. Line pressure continues to increase until the pressure regu-lator valve moves against the spring far enough to open line pressure tothe suction fluid circuit. Excess line pressure at the middle of the valvethen feeds the suction fluid circuit and flows back to the oil pump.When this occurs, pump output capacity is regulated into minimum linepressure.
EXAMPLE B: MAXIMUM LINE PRESSURE (maximum throttle)The pressure regulator valve is constantly regulating pump volume intothe line pressure required to operate the transmission properly. At higherthrottle positions greater line pressure is required to hold the clutchesand the brake band. Therefore, the Transmission Control Module (TCM)signals the variable force motor (404) to increase throttle signal fluidpressure (see page 40 for a complete description of force motor opera-tion). Throttle signal fluid pressure assists spring force and moves theboost valve (205) against the pressure regulator valve. At maximumthrottle, throttle signal fluid pressure moves the pressure regulator valveenough to block line pressure from entering either the suction or ‘con-verter in’ fluid circuits. Without a fluid circuit to direct line pressureinto at the pressure regulator valve, line pressure increases to a maxi-mum. Under normal operating conditions, line pressure is regulatedbetween these minimum and maximum points.
Pressure Regulation in ReverseLine pressure is boosted in a similar manner during Reverse (R) gearoperation. When Reverse is selected, reverse fluid is routed between thetwo lands on the boost valve (205). Because the valve land on the sideclosest to the pressure regulator valve is larger, reverse fluid pressuremoves the boost valve against the pressure regulator valve. This assistsspring force and throttle signal fluid pressure, thereby increasing linepressure.
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PRESSURE REGULATOR VALVE TRAIN (203-208)Pressure Regulator Valve (208)The pressure regulator valve regulates line pressure according to vehicleoperating conditions. This line pressure is directed into: (a) the ‘con-verter in’ fluid circuit which is routed to the converter clutch controlvalve (210) and, (b) to the pump suction fluid circuit as part of thepressure regulation (see page 28). Pressure regulation is controlled bythe pressure regulator spring (207), throttle signal fluid pressure andreverse fluid pressure.
Boost Valve (205)Acted on by throttle signal fluid pressure from the force motor solenoid(404), it moves against the pressure regulator valve. This action movesthe pressure regulator valve to increase line pressure. Therefore, as throttleposition increases and the TCM increases throttle signal fluid pressureat the force motor solenoid, line pressure increases. Also, when Reverse(R) gear range is selected, reverse fluid pressure moves the boost valveagainst the pressure regulator valve to increase line pressure further.
Throttle Signal Accumulator Assembly (214-217)Throttle signal fluid pressure acts on the throttle signal accumulatorpiston (214) in all gear ranges. This pressure moves the piston againstthrottle signal accumulator spring (215) force, thereby dampening anypressure irregularities occurring in the throttle signal fluid circuit. How-ever, this dampening only affects irregular pulses in the fluid circuit andnot the normal changes in throttle signal fluid pressure as determined bythe TCM at the force motor solenoid (404).
TORQUE CONVERTER CLUTCH (TCC) CONTROL VALVE (210)TCC ReleasedThe converter clutch control valve (210) is held in the release positionby the converter clutch control valve spring (211) (as shown). Thisallows ‘converter in’ fluid to enter the release fluid circuit, flow to theconverter and keep the converter clutch released. Fluid exits the con-verter in the apply fluid circuit. Apply fluid flows through the converterclutch control valve and into the cooler fluid circuit.
TCC Apply
To apply the converter clutch, solenoid signal fluid moves the controlvalve (210) against spring force. This blocks ‘converter in’ fluid fromentering the release fluid circuit and opens the release fluid circuit to anexhaust passage. At the same time, line pressure flows through the valveand feeds the apply fluid passage. Apply fluid is routed to the converterto apply the converter clutch and fill the converter with fluid.
COMPONENTS LOCATED IN THE OIL PUMP ASSEMBLY
Figure 27
HYDRAULIC CONTROL COMPONENTS
210
211
212
213
216
217
215
214
206207206 208205204203
BOOST PRESSURE REGULATOR
C O N V C L C O N T R O L
CAPILLARYRESTRICTION
THROTTLE SIGNALACCUMULATOR
ASSEMBLY(214-217)
EX
T H R O T T L E S
I G N A L
EX L I N E
L I N E
S U C T I O N
C O N V E R T E R
I N
R E V E R S E
THROTTLE SIGNAL
C O N V
I N
R E L E A S E
E X
T O C O O L E R
A P P L Y
L I N E
E XSOLENOID SIGNAL
PUMPASSEMBLY(10)
LINE
SUCTION
LINE
S U C T I O N
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HYDRAULIC CONTROL COMPONENTS
VALVES LOCATED IN THE CENTER SUPPORT
R E V L O
C K O U T
O V E R R U N
L O C K O U T
S O L S I G R E V E R S E
R E V C L
R E V E R S E
E X
E X
E X
4 T H C L U T C H
1 -
2
O V E R
R U N
C L U
T C H
L I N E
4 T H
C L F D
2
4 T H
C L F D
2 CENTER
SUPPORTASSEMBLY
30(701)
E X
SOLENOID SIGNAL
OVERDRIVE LUBE
702
703
704
705
SOMEMODELS 702
703
707
706
REVERSE LOCKOUT VALVE (706)This valve prevents the reverse clutch from applying when Reverse (R)gear range is selected and the vehicle is moving forward above ap-proximately 12 km/h (7 mph). Reverse Lockout is not available on allapplications.
Normal Operating ConditionsWhen the vehicle is stationary and Reverse (R) gear range is selected,reverse fluid from the manual valve (326) is routed to the end of the
reverse lockout valve. This fluid pressure moves the valve against springforce, allowing reverse fluid at the middle of the valve to enter thereverse clutch fluid circuit. Reverse clutch fluid applies the reverseclutch and Reverse (R) gear range is obtained.
Reverse Locked OutWhen the vehicle is moving forward above approximately 12 km/h (7mph) and Reverse (R) gear range is selected, the TCM energizes theTCC solenoid. With the solenoid ON, solenoid feed fluid flows throughthe solenoid and fills the solenoid signal fluid circuit. Solenoid signalfluid is routed to the spring end of the reverse lockout valve, therebyassisting spring force to keep the valve closed against reverse fluidpressure. This blocks reverse fluid from entering the reverse clutchfluid circu
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