Hummer H1 Service Manual page 243

5-44 Transmission/Transfer Case
Problem
Vehicle Creeps 1.
In Neutral
2.
Vehicle Moves 1.
In Park
2.
Vehicle Won't 1.
Move In Drive
2.
Range
3.
4.
5.
6.
7.
8.
9.
10. Rear planetary gear set damage:
11. Park pawl spring broken.
12. Turbine shaft ball not seating.
13. Mainshaft splines damaged.
Vehicle Won't
1.
Back Up (No
2.
Reverse)
3.
4.
5.
TRANSMISSION DIAGNOSIS GUIDE (Cont'd)
Potential Cause
Manual valve mispositioned or stuck.
Forward clutch fault.
Manual linkage loose, damaged, misadjusted,
disconnected.
Park pawl, spring, or gear damaged.
Low fluid level.
Shift linkage misadjusted, disconnected, loose.
Pressure switch assembly fault.
Low fluid pressure caused by oil pump fault:
• worn bushing
• failed seal
• broken gears
• loose bolts
Transmission case seal, or gasket failure.
Input or turbine shaft damage (splines worn,
shaft broken)
Roller clutch failure.
Torque converter hub damage.
Forward clutch problem:
• piston seal failure
• clutch plates burned, damaged, missing
• burned reaction plate
• worn teeth
• failed check ball
• broken pinions
• sun gear damage
Low fluid level.
Shift linkage loose, misadjusted, damaged.
Reverse servo fault:
• misassembled
• piston or seal damage
Rear band fault:
• wrong band apply pin
• band worn
Direct clutch fault:
• worn, damaged clutch plates
• check ball leaking or missing
_____________________________________________
1. Remove valve body and repair as needed.
2. Replace transmission.
1. Repair or adjust linkage as required
2. Inspect and replace pawl, spring, or gear.
1. Top off fluid level. If transmission now oper-
ates properly, locate and correct leaks.
2. Correct as required.
3. Replace switch assembly.
4. Remove pump and replace seal. Replace
transmission if pump is damaged.
5. Locate and replace leaking gasket or seal.
6. Replace transmission if either shaft is
damaged.
7. Replace transmission.
8. Replace converter.
9. Replace transmission.
10. Replace transmission.
11. Replace spring.
12. Replace transmission.
13. Replace transmission.
1. Top off fluid. If vehicle now backs up, check
and correct fluid leaks.
2. Repair linkage.
3. Overhaul servo.
4. Check and replace apply pin.
5. Replace transmission.
Correction
®