Hummer H3. Manual — part 1658

TRANSFER CASE LEAK DIAGNOSIS

Transfer Case Leak Diagnosis

to Cleaning and Inspection.

2. Replace the sun gears if they are faulty. Refer to

Transfer Case Disassemble and Transfer Case
Assemble.

Cause

Correction

DEFINITION: A visible indication of an external fluid leak from the transfer case.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Drain plug or fill plug leak

1. Inspect for the correct sealer and the correct amount of

sealer on the plugs.

2. Install the plugs correctly. Refer to Transfer Case Fluid

Replacement.

Vehicle speed sensor (VSS)
leaking

1. Remove the VSS and inspect for the following

conditions:

Cross threaded

Cut or damaged O-ring seal

VSS over tightened causing deformation in the VSS

Refer to Transfer Case Speed Sensor
Replacement.

2. Replace the VSS O-ring seal if it is faulty. Refer to

Transfer Case Speed Sensor Replacement.

3. Replace the VSS if it is faulty. Refer to Transfer Case

Speed Sensor Replacement.

Rear output shaft seal
leaking

1. Inspect for the following conditions:

Overfilled or improper transfer case fluid

Blocked vent

Seal improperly installed, worn or damaged

Seal bore damaged or cracked

Rear output shaft bushing for excessive wear

Slip yoke seal surface for wear or pitting

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

2. Repair or replace the following components if found

faulty:

Adjust or replace the transfer case fluid. Refer to
Transfer Case Fluid Replacement.

Clean or properly route the vent hose.

Replace the slip yoke if the surface could cause
leakage. Refer to Rear Propeller Shaft
Replacement .

Replace the rear output shaft bushing if it is worn.
Refer to Transfer Case Disassemble and
Transfer Case Assemble.

Replace the rear case half if the seal bore is
damaged. Refer to Transfer Case Disassemble
and Transfer Case Assemble.

Replace the rear output shaft seal. Refer to
Transfer Case Output Shaft Seal Replacement -
Rear.

Front output shaft seal
leaking

1. Inspect for the following conditions:

Overfilled or improper transfer case fluid

Blocked vent

Seal improperly installed, worn or damaged

Seal bore damaged or cracked

2. Repair or replace the following components if found

faulty:

Adjust or replace the transfer case fluid. Refer to
Transfer Case Fluid Replacement.

Clean or properly route the vent hose.

Replace the front case half if the seal bore is
damaged. Refer to Transfer Case Disassemble
and Transfer Case Assemble.

Replace the front output shaft seal. Refer to
Transfer Case Output Shaft Seal Replacement -
Front.

Shift shaft seal leaking

1. Remove the encoder motor and inspect for the shift shaft

seal leaking.

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

2. Replace the shift shaft seal. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

Leaking at the vent

1. Transfer case overfilled

1. Inspect for the correct transfer case fluid level.

Refer to Transfer Case Fluid Replacement.

2. Inspect the transmission fluid level. Refer to

Transmission Fluid Check .

3. If the transmission fluid level is low and the transfer

case fluid level is too high, replace the transfer case
input shaft seal. Refer to Transfer Case Input
Shaft Seal Replacement.

4. Inspect for the following conditions:

Seal improperly installed, worn or damaged

Seal bore damaged or cracked

Input shaft seal surface worn, grooved or
damaged

2. Seal the vent with the correct sealer if it is leaking at the

case. Refer to Transfer Case Assemble.

Transfer case to adapter
leak

1. Inspect for the following conditions:

Loose mounting fasteners

Gasket or sealant faulty

The transfer case input shaft seal leaking

2. Repair or replace the following components if found

faulty:

Replace the transfer case input shaft seal. Refer to
Transfer Case Input Shaft Seal Replacement.

Inspect for the following conditions:

Seal improperly installed, worn or damaged

Seal bore damaged or cracked

Input shaft seal surface worn, grooved or
damaged

Repair or replace the loose fasteners. Refer to
Transfer Case Adapter Replacement.

Replace the transfer case gasket or sealer. Refer to

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

REPAIR INSTRUCTIONS - ON VEHICLE

TRANSFER CASE SHIFT CONTROL MODULE REPLACEMENT

Fig. 12: Locating Transfer Case Shift Control Module
Courtesy of GENERAL MOTORS CORP.

Transfer Case Adapter Replacement.

Front case half to rear case
half seam leak

Disassemble and seal the case halves again. Refer to Transfer
Case Disassemble and Transfer Case Assemble.

Case leaking

1. Inspect for a cracked case or case porosity.

2. Replace the faulty case half. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3