GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Inspect for the proper transaxle and gear oil levels prior to performing system diagnosis. Refer to Transfer Case Fluid Replacement .

Low gear oil levels

Faulty oil seals or other type of external leaks may contribute to lower than required fluid levels. Refer to Transfer Case Leak Diagnosis .

Fill to proper level with gear oil. Refer to Adhesives, Fluids, Lubricants, and Sealers .

Worn propeller shaft constant velocity joints

Replace the propeller shaft assembly. Refer to Propeller Shaft Replacement .

Worn bearing in the rear differential torque tube assembly

Replace the torque tube assembly.

Bearing noise within the transfer case

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 internal components, as required.

Gear set whine noise within the transfer case

A whine 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 internal components, as required.
  3. Contributing factors may include:

    • Incorrect backlash between the gear sets
    • Worn or damaged gear teeth
    • Transaxle assembly noise
    • Rear differential noise