HYDRAULIC SYSTEM and REACTION UNIT SERVICE

1
HYDRAULIC SYSTEM and REACTION UNIT SERVICE

• Chapter 5
• Page 98
• Lab manual

2
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
3
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
4
TEST CHART
5
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
6
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
7
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
8
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
9
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
10
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
11
OIL PUMP SERVICE

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

Page 113
12
DISASSEMBLY

• Note position and direction of pump gears before
  removal.
• Look at P5-5, P5-6, and P5-7.

Page 114
13
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
14
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
15
BAND SERVICE

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

Page 119
16
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.

17
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
18
page 121
19
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
20
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
21
SERVOS

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

page 123
22
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
23
INSPECTION
Page 124
24
ASSEMBLY
Page 124
25
SELECTIVE APPLY PINS
Page 124
26
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
27
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
28
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
29
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
30
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
31
AIR TESTING

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

page 140
32
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
33
ROLLER CLUTCHES

• 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.

page 142
34
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
35
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
36
CASE STUDY

• Understand basic theories.
• Listen to everyone.
• Believe no one.
• Prove it to yourself.