Differential Side Gear and Pinion Noise

Differential side gears and pinions seldom cause noise since their movement is relatively slight on straight ahead driving. Noise produced by these gears will be most pronounced on turns. Pinion bearing malfunctions can be distinguished because the pinions rotate at higher speeds than differential side bearings and the axle shaft bearings. Rough or brinelled pinion bearings produce a continuous low pitched-whining or scraping noise starting at a low speed. Side bearings produce a constant rough noise pitched lower than pinion bearing noise. Side bearing noise may also fluctuate in the previous rear wheel bearing test.