have just replaced my final drive after explaining to BMW why it should be done as a goodwill gesture. There is no more leaking of oil from a seal running in what looks like a wear groove on the axle, nor is there a nasty graunching noise on the overrun. As a bonus, the new FD has a drain plug in a sensible place so oil changes are quick and simple. At less that 4 years old and 20,000 miles this sort of repair should not have been required but all credit to Jim Carrie for sorting it outside the normal warranty period. All I had to pay for was the labour to fit it, but having made a contribution to the repair I get the guarantee on it.