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.