GM Service Manual Online
For 1990-2009 cars only

Oil Is Leaking From The Vent Hose

Probable Causes

Action

Transfer case is overfilled with transfer case oil.

Drain the transfer case to the proper oil level. Refer to Oil Replacement .

Oil Leaking From The Front Or Rear Output Shafts

Probable Causes

Action

The vent hose is kinked or plugged.

Inspect the vent hose for kinks or plugging.

Reroute or unplug the vent hose as necessary.

Output shaft seal is damaged or improperly installed.

Replace the leaking output shaft seal.

Oil Is Leaking From The Transfer Case Half Or Adapter

Probable Causes

Action

Loose transfer case bolts

Tighten the transfer case bolts. Refer to Fastener Tightening Specifications .

Fill Or Drain Plug Leaking

Probable Causes

Action

Plug is loose or missing a thread sealant.

Perform the following procedures:

    • Remove the plug.
    • Clean the threads.
    • Apply a sealant tape.
    • Install the plug and tighten to specifications. Refer to Fastener Tightening Specifications .

Transfer Case Is Noisy

Probable Causes

Action

Bearing or chain worn

Inspect the inside of the transfer case for worn parts.

Low oil level

Check the oil level.

Add oil if necessary. Refer to Oil Replacement .

Driveline Vibration

Probable Causes

Action

Front or rear propeller shaft is bent or out of balance

Inspect the propeller shaft for damage.

Balance or replace the propeller shaft if necessary.

For front propeller shaft replacement, refer to Front Propeller Shaft Replacement .

For rear propeller shaft replacement, refer to Rear Propeller Shaft Replacement .

Front propeller shaft CV-joint is worn or damaged

Inspect the propeller shaft for damage.

Replace the front propeller shaft if necessary.

Refer to Front Propeller Shaft Replacement .