BMW 3 Series Diff Failure With Collapsed Bearings
At GP Motor Works we have seen several BMW 3 Series vehicles where the rear differential has needed to be replaced or reconditioned due to failure.
BMW maintains their differential oil is rated as a “lifetime fluid” and never needs to be changed. However, in many of cases, the diff oil can get dirty and/or water contaminated or it can leak when the gasket fails. Unless this is checked it will lead to mechanical failure of the gears and bearings. As a result, we advise you to book your car in for a differential oil service every 60,000 kms.
In this particular instance, the bearings had failed due to oil leakage. If the oil level gets dangerously too low it may cause the gears to whine.
Besides oil leakage/contamination there are other differential components which fail. These include the megatronic (EGS) control unit, clutches and the torque converter.
We advise our clients to periodically look out for small pools of oil on the garage floor. If you find any oil spots located more or less in between rear wheels then give us a call.