Inspect for proper gear oil levels prior to performing system diagnosis.

Low gear oil levels

Faulty oil seal or other types of leaks may contribute to lower than required fluid levels.

Refer to Rear Axle Lubricant Leak Diagnosis .

Fill to the proper level with gear oil, GM P/N 12378514 (Canadian P/N 88901045).

Refer to Differential Oil Replacement .

Worn or loose axle mounts

Repair or replace axle mounts as required.

Refer to Differential Housing Support Bushing Replacement : Rear  → Front .

Worn propeller shaft constant velocity or universal joints

Replace the universal joints as required. Refer to Propeller Shaft Replacement .

If constant velocity joint is damaged, replace the propeller shaft. Refer to Propeller Shaft Replacement .

Worn propeller shaft centre bearing assembly

Replace the centre bearing assembly.

Refer to Propeller Shaft Replacement .

Bearing noise within axle assembly

This type of noise will decrease or increase relative to the vehicle speed.

1. Check for the proper fluid level. Refer to Differential Oil Replacement .
2. Repair or replace the unit as required.

Gear set whine noise within the carrier assembly caused by incorrect backlash

A whine type of noise will increase or decrease relative to the vehicle speed.

1. Check for the proper fluid level. Refer to Differential Oil Replacement .
2. Repair or replace the unit as required.