Flat spot on the pinion or the ring gear teeth

Replace the pinion and the ring gear. Refer to Drive Pinion and Ring Gear Replacement .

Flat spot on the pinion bearing

Replace the bearing. Refer to Drive Pinion Bearings Replacement .

Worn pinion splines

Replace the pinion. Refer to Drive Pinion and Ring Gear Replacement .

Bent axle shaft

Replace the axle shaft. Refer to Rear Axle Shaft Replacement .