Front

^ An external leak of lubrication can be caused by a faulty internal seal. For example, if the seals which separate the differential from the swivel housings are faulty and the vehicle is operating or parked on an embankment, oil may leak across the axle leaving one swivel with a high level and the opposite swivel and differential lacking lubrication.
^ When investigating leaks or checking oil levels, it is essential that all the lubrication is drained from any housing with a high level and that the other levels are checked.
^ Swivel housing oil (where used) should be checked for signs of grease leaking from the hub bearings and oil contamination of the hub grease.
^ Check that the axle ventilation system is clear, as a blockage can cause internal pressure to force oil past the seals.
^ If the vehicle is driven in deep water with defective oil seals, water may contaminate the lubricants and when checked, give a false impression that the housing has been overfilled with oil.

NOTE: Do not assume that a high oil level is due to over filling or, that a low level is because of an external leak.