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

Transmission noise

Repair or replace as required. Refer to Transmission Replacement for the 5L40-E/5L50-E transmission or Transmission Replacement for the 6L50/6L80/6L90 transmission.

Worn axle shaft constant velocity joints

Replace the constant velocity joints as required.

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. Check 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 80-96 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. Check for the proper fluid level. Fill as required.
2. Repair or replace the unit as required.