Testing Procedure

WARNING: This page is about a different car, the 2006 GMC Sierra, 2006 GMC Cab & Chassis Sierra, 2006 Chevrolet Silverado, and 2006 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Wipe clean the differential case, the ring gear and the differential carrier housing of lubricant. Carefully clean each tooth of the ring gear.
Use a medium stiff brush in order to sparingly apply gear marking compound GM P/N 1052351 (Canadian P/N 10953497) or equivalent to all of the ring gear teeth.

Fig 1: Applying Gear Marking Compound To Ring Gear Teeth
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Avoid turning the ring gear excessively.

Using a wrench, turn the drive pinion flange/yoke so that the ring gear rotates at least 3 full revolutions.
Turn the drive pinion flange/yoke in the opposite direction so that the ring gear rotates at least 3 full revolutions in the opposite direction.
Observe the pattern on the ring gear teeth. Compare the pattern with the following illustrations.
Once the proper pattern is obtained, continue the assembly of differential carrier. Refer to Differential Carrier Assembly - Assemble .