For 1990-2009 cars

Cause | Correction
--- | ---
DEFINITION: Inspect for proper gear oil levels prior to performing system diagnosis. Operate the vehicle turning in tight circles, in both left and right directions. Moan, groan, chatter, or a pulsing type concern may indicate a pump or clutch park problem within the axle assembly.
Worn or loose rear axle mount bolts | Repair or replace as required.
Worn axle shaft constant velocity joints | Replace the axle shaft as required.
Worn wheel bearings | Replace the wheel bearings as required.
Incorrect gear oil | Replace the gear oil, GM P/N 9986115.
Worn differential side and/or idler gears and worn crosspin | Replace the differential carrier assembly as required.