HYDRAULIC SYSTEM and REACTION UNIT SERVICE

Chapter 5 Page 98

Lab manual

DIAGNOSE HYDRAULIC and VACUUM CONTROL

SYSTEMS The best way to identify the exact

cause of transmission problems is to use the results of a road test:

Logic Oil charts circuit charts for the

transmission being worked on.Page 98

PRESSURE TESTS

If the road test does not find the problem, perform a pressure test.

Check minimum line in all ranges. Check maximum line in all ranges. What does that mean?

Page 99

TEST CHART

Idle 1200 RPM 1200 Max TVP

R

N

D

3

2

1D

VALVE BODY SERVICE

Drain transmission. Remove valve body disassemble

halves check for stuck valves. Do NOT remove valves until you

have found the problem. Use a Polaroid camera for check ball

location.

Page 105

CLEANING AND INSPECTION

Individual VB parts are not sold separately.

Use spray carb cleaner, WEAR EYE PROTECTION.

Place unlubricated valve in its bore, hold vertical it should fall out by its own weight.

Page 107

VALVEBODY REASSEMBLE

Use notes. Photos Manuals Place valve body gaskets over

separator plate, Gasket can NOT cover any holes in plate.

DO NOT OVERTIGHTEN VB BOLTS.

Page 110

GOVERNOR SERVICE

If diagnostic road test indicates a governor problem.

Remove, disassemble, clean, and inspect.

Two main types of governor problems,– Late shifts– Not starting in first gear from a stop.

Page 111

DISASSEMBLY

Most governors have a Primary and Secondary valve.

Valves should be free to move from their own weight.

Inspect drive gear, if it has one. Clean thoroughly.

Page 112

REASSEMBLY

Do not mix up primary and secondary weights or springs.

Install valves correctly, see fig. 5-20. If governor pressure gauge reads

less than 2 PSI ValveBody problem. If governor pressure gauge reads

more than 2 PSI Governor problem.

Page 112

OIL PUMP SERVICE

The oil pump should be carefully inspected during overhaul, especially if Trans had low line pressure.

Page 113

DISASSEMBLY

Note position and direction of pump gears before removal.

Look at P5-5, P5-6, and P5-7.

Page 114

INSPECTION Inspect the pump bore for scoring on

both its bottom and sides. A front pump bushing with two much

clearance will allow gears to run off center.

Check stator splines for wear. Check all bushings for wear and size. Check halves for warpage.

Page 116

REASSEMBLY

Pump bushing and seal should be installed with proper driver.

Lube bushing and seal lip. Coat pump gears in Trans fluid

before assembly. Use proper tools to align pump

halves.

Page 118

BAND SERVICE

Single or double wrap designs. Cast iron or flex type. Do not flatten out flex band or lining

may crack.

Page 119

INSPECTION Look for chipping, cracks, burn marks,

glazing, nonuniform wear patterns, and flaking.

The drum surface should be checked for discoloration, scoring, glazing, and distortion.

Cast drums should be sanded with 180-grit sandpaper.

The surface of the drum should be flat, check all stamped drums.

BAND ADJUSTMENT Every band must be adjusted when

installed. Some transmissions do not require

periodic band adjustment. Some use adjusting screws, and

some use selective apply pins. The timing of the band application

has a lot to do with how the shift feels. page 120

page 121

SERVO and ACCUMULATOR

Some servos are serviceable in the car.

Some accumulators are serviceable in the vehicle.

One of the main problems are leaks. Check bores for gouges and scoring.

page 122

ACCUMULATORS Remove accumulator cover snap

ring. Remove cover, piston and spring. Be sure to note order of disassembly. Manuals may have poor pictures. Piston in first or spring in first? Check seals rubber, Teflon, or steel.

page 122

SERVOS A servo is connected to a band. Same checks as for a accumulator.

page 123

SEALS

Most original equipment servo seals are of the Teflon type.

Cast iron hook ring may be supplied as replacements.

Be sure to check ring size in the bore it goes in.

Check that the ring are free in ring groves.

page 124

INSPECTION

Page 124

ASSEMBLY

Page 124

SELECTIVE APPLY PINS

Page 124

CLUTCH PACKS Two types of clutch packs: Rotating drum - Case grounded All clutch plates are held in place with

snap rings, with some selective thickness.

There may be two or more snap rings of the same diameter but different thickness or shape.

page 126

DISASSEMBLY Remove snap ring retaining the

pressure plate. Remove friction and steel plates. Use clutch piston spring compressor

to compress spring and remove snap ring.

Remove retainer, springs, and piston. Note direction of seal installation.

page 127

INSPECTION AND CLEANING Make sure that you keep the parts of

each clutch separate. Clean all parts, and air dry. Check all splines. Check retainers and springs. Check wave plates for scoring, height. Check ring groves, bushings on drums.

page 132

CLUTCH PACK REASSEMBLY Install new seals and lube before

installation. Soak frictions in ATF prior to

installation. If clutch has a belleville spring the lower

pressure plate must be rounded on the bottom side.

page 135

CLEARANCE CHECKS Adjust clearance by:

– Selective snap rings – Selective pressure plates– Selective apply rings– Oversize steel plates

Non shifting clutch packs have less clearance than shifting clutch packs.

Clutches with Belleville spring .025” max.

page 139

AIR TESTING Check with drums on pump and, Check before valve body is installed.

page 140

ONE-WAY CLUTCHES

The durability of these clutches relies on constant fluid flow during operation.

If failure has occurred trace lube circuit and verify volume and pressure.

page 141

ROLLER CLUTCHES

page 142

Check rollers for roundness. Check springs for distortion. Check races for any irregularities. One spring for each roller. Sand races with a crosshatch

pattern. Check for correct direction of

operation.

SPRAG CLUTCHES Sprag element can not be

disassembled. If an element falls out replace the sprag. Check races for any irregularities. Sand races with a crosshatch pattern. Check for correct direction of operation.

page 142

TRANS COOLER SERVICE Flush cooler at time of overhaul. Check lines for leakage. Check for rubbing on pan,

crossmember, etc. If the fluid can not circulate, it can not

cool. Some radiator Trans coolers have

internal filters.page 142

CASE STUDY

Understand basic theories. Listen to everyone. Believe no one.

Prove it to yourself.