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MT2923EN

MT4108EN

Mechanics Tips

MD 3070PT SeriesTransmissions

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i

MT2923EN

Mechanics

Tips

Allison TransmissionMD 3070PT

February 1995Rev 1: June 2000

Printed in U.S.A. Copyright 2007 Allison Transmission, Inc.

Allison Transmission, Inc.

P.O. Box 894 Indianapolis, Indiana 46206-0894

www.allisontransmission.com

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ii

IM PORTANT SAFETY NOTICE

IT IS YOUR RESPONSIBILITYto be completely familiarwith the warnings and cautions used in this manual. Thesewarnings and cautions advise against using specific serviceprocedures that can result in personal injury, damage to theequipment, or cause the equipment to become unsafe. Thesewarnings and cautions are not exhaustive.Allison Transmissioncould not possibly know, evaluate, or advise the service trade of

all conceivable procedures by which service might be performedor of the possible hazardous consequences of each procedure.Consequently, Allison Transmission has not undertaken any suchbroad evaluation. Accordingly, ANYONE WHO USES ASERVICE PROCEDURE OR TOOL WHICH IS NOTRECOMMENDED BY ALLISON TRANSMISSION MUSTfirst be thoroughly satisfied that neither personal safety nor equip-ment safety will be jeopardized by the service procedures used.

Proper service and repair are important to the safe and reliableoperation of the equipment. The service procedures recom-mended by Allison Transmission and described in this manualare effective methods for performing service operations. Someservice procedures require using tools specially designed for theprocedure. Use special tools when and as recommended.

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iii

TABLE OF CONTENTS

Paragraph Description Page

SECTION I PREVENTIVE M AINTENANCE11. Periodic Inspection And Care . . . . . . . . . . . . . . . . . . . . . . . 1

12. Importance Of Proper Transmission Fluid Level. . . . . . . . . 1

13. Transmission Fluid Check . . . . . . . . . . . . . . . . . . . . . . . . . . 2

14. Keeping Fluid Clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

15. Fluid Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

16. Transmission Fluid And Filter Change Intervals . . . . . . . . . 7

17. Transmission Fluid Contamination . . . . . . . . . . . . . . . . . . . 8

18. Transmission Fluid And Filter Change Procedure. . . . . . . . 919. Fluid Leak Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

110. Breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

111. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

112. Transmission Stall Test And Neutral

Cool-Down Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

SECTION II REMOVING TRANSMISSION

21. Draining Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

22. Disconnecting Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

23. Uncoupling From Driveline, Engine, And Vehicle . . . . . . . 22

24. Removing The Transmission . . . . . . . . . . . . . . . . . . . . . . . . 22

25. Removing Output Flanges Or Yokes . . . . . . . . . . . . . . . . . . 22

SECTION III PREPARING THE TRANSM ISSION FOR

INSTALLATION31. Checking Input Components . . . . . . . . . . . . . . . . . . . . . . . . 23

32. Installing Output Flange Or Yoke . . . . . . . . . . . . . . . . . . . . 23

33. Installing PTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

34. Installing Scavenge Pump . . . . . . . . . . . . . . . . . . . . . . . . . . 24

35. Installing Fill Tube And Seal . . . . . . . . . . . . . . . . . . . . . . . . 25

36. Checking Plugs And Openings . . . . . . . . . . . . . . . . . . . . . . 25

SECTION IV PREPARING VEHICLE FOR TRANSMISSION

INSTALLATION

41. Engine, Transmission Adaptation Requirements. . . . . . . . . 26

42. Checking Flexplate Drive Assembly . . . . . . . . . . . . . . . . . . 28

43. Chassis And Driveline Inspection . . . . . . . . . . . . . . . . . . . . 29

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Paragraph Description Page

44. Cooler, Filter, And Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

45. Checking Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

SECTION V INSTALLING TRANSMISSION

INTO VEHICLE

51. Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

52. Mounting To Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

53. Installing Transmission Mounting Components . . . . . . . . . 36

54. Coupling To Driveline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

55. Connecting Power Takeoff Controls . . . . . . . . . . . . . . . . . . 36

56. Connecting Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3757. Connecting Speedometer Drive . . . . . . . . . . . . . . . . . . . . . . 37

58. Connecting Electrical Components . . . . . . . . . . . . . . . . . . . 38

59. Filling Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

510. Installation Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

SECTION VI CHECKS AND ADJUSTM ENTS

61. Installation Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

62. Road Test And Vehicle Operation Checklist . . . . . . . . . . . . 42

SECTION VII CUSTOM ER SERVICE

71. Owner Assistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

72. Service Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

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PREFACE

This handbook is a mechanics reference for removing, installing, or maintaining anMD 3070PT Automatic Transmission. All features of the transmission and the vehi-cle involved in installation procedures are discussed. The information presented will

help the mechanic remove, install, and maintain the transmission in a manner thatassures satisfactory operation and long service life. For additional detailed informa-tion, refer to the appropriate transmission service manual and electronic controlstroubleshooting manual.

TRADEM ARKS USED

DEXRON

is a registered trademark of General Motors Corporation.

Pro-Link

is a registered trademark of Microprocessor Systems, Inc.

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CONVERTER HOUSINGMODULE

PTO DRIVE GEARCONVERTER HOUSING

ROTATING CLUTCH MODULE

TURBINE SHAFTC1 CLUTCHC2 CLUTCH

CONTROL MODULEHYDRO-ELECTRONIC CONTROLS

MAIN HOUSING MODU MAIN HOUSING C3 CLUTCH C4 CLUTCH C5 CLUTCH

P1 MODULE

CONVERTER MODULETURBINE

PUMPSTATORLOCKUP

CLUTCH/DAMPER

FRONT SUPPORT/OIL PUMP MODULE FRONT SUPPORT

OIL PUMP

MD 3070PT

SEVEN-SPEED WITH TRANSFER CASE, CLOSE RAT

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MD 3070PT TRANSMISSION LEFT REAR-VIEW

MD 3070PT TRANSMISSION RIGHT FRONT-VIEW

E01707.02

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V01725

MAIN

C2

C4

C1

LU

C3

MD 3070PT TRANSMISSION BOTTOM-VIEW

C6

C5

V01726

T-CASECONNECTOR

C7

MAIN

MD 3070PT TRANSFER CASE FRONT-VIEW

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1

PREVENTIVE

MAINTENANCE

SECTION

I

11. PERIODIC INSPECTION AND CARE

Clean and inspect the exterior of the transmission at regular intervals. Severity of

service and operating conditions determine the frequency of these inspections.

Inspect the transmission for:

loose bolts transmission and mounting components

fluid leaks repair immediately

loose, dirty, or improperly adjusted throttle sensor linkage

damaged or loose hoses

worn, frayed, or improperly routed electrical harnesses

worn or out-of-phase driveline U-joints and slip fittings

A label describing on-vehicle welding precautions is available from your authorized

Allison service dealer and should be installed in a conspicuous place. A vehicle used

in a vocation that requires frequent modifications or repairs involving welding must

have an on-vehicle welding label.

12. IM PORTANCE OF PROPER TRANSMISSION FLUID LEVEL

Transmission fluid cools, lubricates, and transmits hydraulic power.

Always maintain proper fluid level. If fluid level is too low, the torque

converter and clutches do not receive an adequate supply of fluid and the

transmission overheats. If the level is too high, the fluid aerates causing

the transmission to shift erratically and overheat. Fluid may be expelled through the

breather or dipstick tube when the fluid level is too high.

CAUTION: When welding on the vehicle:

DO NOT WELDon the vehicle without disconnecting from

the ECU all control system wiring harness connectors.

DO NOT WELDon the vehicle without disconnecting ECU

battery power and ground leads.

DO NOT WELDon any control components.

DO NOT CONNECTwelding cables to any control components.

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