08 K12GT - Weird vibration from drive shaft/final drive

I was out for a ride yesterday and about 10 miles from home i started to feel a strange vibration from the drive train. It seemed more pronounced during deceleration. When I got home the FD was really hot. I also had heavy oil residue on the tire and around the brake caliper (which is mounted on the low side of the wheel...this is German engineering???). I slowly removed the drain/filler plug and got the unpleasant surprise of a hot oil bath (I was expecting there to be little to no oil in the unit). I replace the FD oil about 4k miles ago and have had no problems.... until yesterday! Any ideas on what happened and where I go from here?? Thanks for any troubleshooting or diagnostic tips.

Sounds like bearings and seal in the final drive. Time for a rebuild or a new one.

tonyfr said:

Sounds like bearings and seal in the final drive. Time for a rebuild or a new one.

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Is this normal for a bike with 27K miles that has had regular service? Is there any way around this or are the components BMW uses inferior?

It's pretty early, but it sure seems like you are having a big bearing and seal failure.

Read the "EVO Paralever final drives" section toward the bottom: http://vamotorrad.com/benchwork/

AntonLargiader said:

It's pretty early, but it sure seems like you are having a big bearing and seal failure.

Read the "EVO Paralever final drives" section toward the bottom: http://vamotorrad.com/benchwork/

Click to expand...

Thanks Anton, Brought my FD to a local dealership and he told me pretty much what you say in the link above. He did say that BMW no longer sells the gear sets and if, upon inspection of the opened final drive, there are any issues with the gearset the only alternative is to buy a complete final drive assembly. This is very frustrating and discouraging news given the low mileage on the bike. Now I sit and wait.

Thanks also for taking the time to write the OTL article on final drives. It was easy to follow and sheds a lot of light on the mechanics and why proper fluids are required. Another thing I learned from my trip to the local dealer is that Mobil 1 fully synthetic 75/140 is not a suitable substitute for the BMW C-SAF-XO fluid. Though I only did 2 changes with the Mobil 1 the dealer seemed to think that may be a contributing factor to the early failure.

I only use the SAF-XO, but the bearing that fails does not run in the oil at all. However, the pinion bearings (which are the real weak link here) do, and I think that when they start to go they put more stress on the axle bearings. So I can sort of see what your shop is saying; it depends how it was presented.

Axle wear is not common, and gear tooth wear is practically unheard of.