Rear Bearing Noise

A rough sounding rear wheel bearing produces a noise which continues while the vehicle is coasting at low speed and the transmission in "NEUTRAL". This noise may diminish while braking gently. With the rear of the vehicle lifted and supported, spin each wheel by hand while listening at the hubs for evidence of a rough (noisy) wheel bearing.

Rear Axle Wheel Bearing Diagnosis
Consider the following factors when diagnosing the condition of the wheel bearing:
1. Determine the type of bearing noise.
2. General condition of all parts during disassembly and inspection.
3. Classify the failure with the aid of the illustrations.
4. Make all repairs following recommended procedures.

Wear (Minor)





A light pattern on the races and rollers are caused by fine abrasives. Clean all parts end housings. Check seals and replace bearings if rough or noisy. Replace shaft if it is damaged.

Wear (Major)





Heavy wear patterns on the races and rollers are caused by fine abrasives. Clean all parts and housings. Check seals and replace the bearings if rough or noisy. Replace the shaft if it is damaged.


Brinelling





Surface indentations in the raceway are caused by roll either under impact loading or vibration while the bearing is not rotating. Replace the bearing if it is rough or noisy. Replace the shaft if it is damaged.

Indentations





Surface depressions on the race and rollers are caused by hard particles of foreign material. Clean all parts and housings. Check the seals and replace the bearings if they are rough or noisy. Replace the shaft if it is damaged.

Single Edge Pitting





Pitting of the surface metal is a result of fatigue. Pitting is found at one edge of race and rollers. Replace the bearing and clean all of the related parts. Replace the shaft if it is damaged.

Double Edge Pitting





Pitting of the surface metal is a result of fatigue. Pitting is found at both edges of the race and rollers. Replace the bearing and clean all of the related parts. Replace the shaft if it is damaged.

Misalignment





Outer race misalignment is caused by a foreign object that is not allowing the race to seat properly. Replace the bearing and make sure races are properly seated. Replace the shaft if the bearing surface is damaged.

Frettage





Frettage is a result of corrosion that occurs by small relative movement of parts with no lubrication. Replace the bearing and clean all of the related parts. Check the seals for damage, proper fit and lubrication. Replace the shaft if it is damaged.

Smears





Smearing of metal is due to slippage. Slippage can be caused by poor fits, lack of lubrication, overheating, overloads or handling damage. Replace the bearing and clean all of the related parts. Check for proper fit and lubrication.

Knock at Low Speeds
Low-speed knock can be caused by worn universal joints or a side gear hub counterbore in the case that is worn oversize. Inspect and replace the universal joints or case and side gears as required.

Backlash Clunk
Excessive clunk on acceleration and deceleration can be caused by a worn rear axle pinion shaft, worn case, excessive clearance between the axle and the side gear splines, excessive clearance between the side gear hub and the counterbore in the case, worn pinion and side gear teeth, worn thrust washers, and excessive drive pinion and ring gear backlash. Remove worn parts and replace as required. Select close fitting parts when it is possible. Adjust pinion and ring gear backlash.