GMC 1989 Light Duty Truck, Repair Manual, Page: 761 / 998

400/475 AUTOMATIC TRANSMISSION 7A2-1
SECTION 7A2
400/475 AUTOMATIC TRANSM ISSION
CONTENTS
T R A N S M I S S I O N D I S A S S E M B L Y ...........7A2-1
G E N E R A L S E R V IC E
IN F O R M A T IO N ................................................ 7A2-1
D I S A S S E M B L Y ..................................................... 7A2-3
Vacuum M odulator A ssem bly ......................... 7A2-3
Pan & Filter A ssem bly .......................................7A2-4
Control Valve A ssem bly .................................... 7A2-4
Solenoid Assem bly ............................................... 7A2-4
Front and Rear Servo A ssem blies .................. 7A2-4
Band A pply Pin Check ......................................... 7A2-4
Governor A s s e m b ly .............................................. 7A2-5
Front End Play Check ........................................7A2-5
Case Extension A ssem bly ..................................7A2-6
Rear U nit End Play Check ............................... 7A2-6
Oil Pump Assem bly .............................................7A2-7
Parking Lock Pawl and A ctuator
Assem bly ..............................................................7A2-7
Forward Clutch A ssem bly ................................... 7A2-8
D irect Clutch A s s e m b ly ........................................ 7A2-8
Intermediate Clutch A ssem bly ........ ;................ 7A2-8
Center Support and Gear Unit
A ssem bly ................... ....................................... 7A2-10
Transmission Case ......................................... 7A2-11
C O M P O N E N T R E P A IR A N D
T R A N S M I S S I O N A S S E M B L Y ............. 7A2-15
Park Lock Pawl and A ctuator
Assem bly ...... .....................................................7A2-15
Rear Band and Selective Thrust
Washers .................................... .........................7A2-16
Gear U nit and Output Carrier
Assem blies .........................................................7A2-16
Speedometer D rive Gear
Speed Sensor R otor Replacement ............ 7A2-16
Gear U nit A s s e m b ly .......................................... 7A2-17
Reaction Carrier Assem bly ............................. 7A2-18
Intermediate Clutch Piston ................................7A2-20
Low Clutch Roller Assem bly ........................ 7A2-21
Direct Clutch and Intermediate
Roller A ssem bly .............................................7A2-21
D irect Clutch Piston ............................................7A2-22
Direct Clutch Assem bly ......................................7A2-22
Center Support and Gear Unit
Assem bly .............................................................. 7A2-24
Intermediate Clutch Assem bly ........................ 7A2-24
Direct Clutch A ssem bly and Front
B a n d ..................................................................... 7A2-25
Forward Clutch Assem bly .................................7A2-25
Turbine Shaft Rem oval .................................... 7A2-26
Oil Pump A ssem bly .......................................... 7A2-29
Pump Body ...................................................... 7A2-29
Gear Clearance ............................................... 7A2-29
Pump Cover ..................................................... 7A2-30
Rear U nit End Play Check ............................. 7A2-31
Front U nit End Play Check ...........................7A2-32
Governor A s s e m b ly .............................................. 7A2-32
Driven Gear R e p la ce m en t...........................7A2-32
Rear Servo Accum ulator Assem bly ............ 7A2-34
Front Servo A ssem bly .......................................7A2-35
Control Valve A ssem bly ..................................7A2-36
Pan and Filter Assem bly .................................7A2-39
Torque Converter ............................................... 7A2-40
T O R Q U E S P E C IF IC A T IO N S ......................7A2-42
S P E C IA L T O O L S ......................... ..................... 7A2-43
B U S H IN G R E P L A C E M E N T ........................ 7A2-45
TRAN SM ISSIO N D ISA SSEM B LY
GENERAL SERVICE IN F O R M A T IO N
• Teflon Oil Seal Rings: During disassembly, check
seals for damage and make sure that they rotate
freely in their grooves. Inspect the grooves for
dirt, burrs or other damage.
• Thrust washers and surfaces: These washers and
the surfaces they engage may appear polished.
This is a normal condition and does not indicate
damage.
• Thoroughly clean the exterior o f the
transmission.
• A s the unit is disassembled clean the assemblies
or com ponents so that proper inspection can be
made.
■*4-
Install or Connect (Figure 3)
T ools Required:
J 3289-20 Base
J 8763-02 H olding Fixture
1. J 8763-02 onto transmission case.
9
Important
D o not overtighten the tool as case damage
may result.
2. Transmission and holding fixture into J 3289-20.
«--► Remove or Disconnect (Figure 1)
Torque converter (1).
3. Fixture pin.
4. Drain transmission fluid.