Transfer case is overfilled with transfer case oil.

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

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.

Loose transfer case bolts

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

Plug is loose or missing a thread sealant.

Perform the following procedures:

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 .

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 in Propeller Shaft.

For rear propeller shaft replacement, refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.

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 in Propeller Shaft.