Differential Assembly: Testing and Inspection

Rear Drive Axle and Differential

Complaint - Oil Leaks

An external leak of lubrication from the hub seals can be caused by a faulty internal seal. For example, if the seals which seperate the differential from the hubs are faulty and the vehicle is operating or parked on an embankment, oil from the differential may flood one hub resulting in a lack of lubrication in the differential.

When a seal is found to be leaking check the axle ventilation system, as a blockage can cause internal pressure to force oil past the seals.

Illustrations of oil seal locations are given in Description and Operation.

When investigating hub seal leaks check the grease for dilution with oil. Also check the differential oil level for signs of metal particles in the oil and the condition of internal seals.

If the vehicle is driven in deep water with defective oil seals, water may contaminate the lubricants and raise the differential oil level, giving a false impression that the housing has been overfilled. Do not assume that a high oil level in the differential is due to overfilling , or that a low fluid level is due to an external leak.