Rear drive seepage

I have a 04 BMW R1150R with 31500 miles. Looking on the bottom of the rubber boot I see fluid leaked out and some on the arm below it.

So question is this a big or small problem. My bmw shop said they usually take it all apart to get to the clutch seal and spline area

I have a 04 BMW R1150R with 31500 miles. Looking on the bottom of the rubber boot I see fluid leaked out and some on the arm below it.

So question is this a big or small problem. My bmw shop said they usually take it all apart to get to the clutch seal and spline area

Evening Tennmoto

What rubber boot? The one on the final drive end or on the transmission end?

If on the final drive end then you probably have a leaking/seeping pinion seal.

Not exactly rocket science to replace but a bit of a real pain if you haven't done one before or have the correct tools.

If on the final drive end & IF you are using synthetic gear oil in the final drive than you might try changing to conventional gear oil as sometimes that will slow or stop a pinion seal seep.

Also, make sure that the final drive vent in not plugged. (vent is on top of drive)

If on the trans end then it is even more of a project to replace the rear trans seal.

As DR has said it depends on which end it is coming from. Generally it is from the Final Drive boot and it is weeping out of the final drive input shaft seal.

An important thing to note is that if that is the case, then the amount of work really isn't worth it. Once you have assessed that it is not coming from the gearbox end (this is done by getting a bright flashlight and looking up the tunnel from rear to front and establish that there is not evidence of a trail of oil running down). Once you have established that, my honest advice is, give it a really good clean up and then button it up again. Keep an eye on the FD fluid levels, and also monitor the rubber boot. Then at the next 6000 mile service, release the rubber boot and inspect again. Chances are it will be nothing.

Mine leaked with Synthetic transmission oil, but the leak goes away with dino oil.

Thanks for replies, love the forum