Diagnosing Differential Noise

Diagnosing differential noise is extremely important. And while most vehicle sounds are normal while the vehicle is in motion, there are times when a noise coming from under the car can be a serious matter. Here are a few common “noises” that may come from the rear axle that need immediate attention:

Differential

Whirring…

A “whirring” noise while decelerating at any or all speeds is most likely caused by bad pinion bearings or loose pinion bearing preload. This condition is typically always diagnosed as a bad ring and Pinion gear.

Howling…

A “howl or whine” during acceleration over a small or large speedrange is usually caused by worn ring and pinion gears or improper gear set up.

Rumbling…

“Rumbling or whirring” at speeds over 20 mph can be caused by worn carrier bearings. The noise may change while cornering or turning.

A “Rumble” while cornering or turning may indicate bad wheel bearings.

Clunking and Clicking…

Regular “clunking” or loud “clicking” every few feet may indicate a broken ring or pinion gear tooth.

“Clunking or clicking” when starting to move or getting on and off the gas might be loose yokes, bad u-joints or worn transfer case or transmission parts.

Banging…

“Banging, clicking or clunking” while cornering can be caused by broken cornering gears commonly called “spider gears”, lack of sufficient positraction lubrication, or worn positraction clutches.

A steady vibration that increases with the vehicle’s speed can be caused by worn u-joints or an out of balance driveshaft.

All unusual or strange noises produced by the driveline while driving have a root cause and should be thoroughly investigated to prevent serious damage to the vehicle or the operator. Diagnosing differential noise properly can save a lot.