For 1990-2009 cars

Cause | Correction
--- | ---
Inspect for the proper gear oil levels prior to performing system diagnosis. Refer to Axle Lubricant Change . A light "clunk" type noise during a downshift is to be considered a normal condition.
Loose propeller shaft mounting bolts | Tighten the bolts as required. Refer to Propeller Shaft Replacement .
Worn propeller shaft constant velocity joints | Replace the propeller shaft assembly. Refer to Propeller Shaft Replacement .
Worn axle shaft constant velocity joints | Replace the constant velocity joints as required.
Worn, loose, or missing differential mounts | Repair or replace the differential mounts as required.
Loose torque tube bracket or a damaged bracket bushing | Tighten the bracket bolts or replace the bracket as required.
Worn bearing in the torque tube assembly | Replace the torque tube assembly.
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, replace 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 80-97 km/h (50-60 mph). |

1. Check for the proper fluid level. Fill as required.
2. Replace unit as required.