GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Important: Inspect for the proper gear oil levels prior to performing system diagnosis. Refer to Rear Axle Lubricant Level Inspection .

Low gear oil levels

Faulty oil seals or other type leaks may contribute to lower than required fluid levels. Refer to Rear Axle Lubricant Leak Diagnosis .

Fill to the proper level with the correct gear oil and friction modifier additive. Refer to Adhesives, Fluids, Lubricants, and Sealers and Rear Axle Lubricant Replacement .

Worn, loose, or damaged axle mount and/or bracket

Repair or replace the axle mount and/or bracket as required.

Bearing noise within the differential assembly

A grinding or roar type noise will increase or decrease relative to the vehicle speed.

  1. Inspect for the proper fluid level. Fill as required.
  2. If the noise continues, repair or replace the unit as required.

Gear set whine noise within the differential assembly

A whine type noise will increase or decrease relative to the vehicle speed, approximately 31-37 km/h (50-60 mph). Typical causes of a gear set whine type noise may include incorrect backlash and/or pinion depth adjustment or worn or scored gear set teeth.

  1. Inspect for the proper fluid level. Fill as required.
  2. Repair or replace the unit as required.