R1100RT, xmission leaking from the rear?

[DGuy]

Greetings:

 

Opened the rubber boot just forward of the final drive unit and a couple of ounces of oil came out.

 

Checked level of lube in Final Drive and it is full.

 

The obvious thing to me is that he transmission is leaking from the rear.

 

If this is happening, is there a seal that can be replaced? And if so, with the transmission in situ?

 

Thanx in advance

 

[Boffin]

Greetings:

 

Opened the rubber boot just forward of the final drive unit and a couple of ounces of oil came out.

 

Checked level of lube in Final Drive and it is full.

 

The obvious thing to me is that he transmission is leaking from the rear.

 

If this is happening, is there a seal that can be replaced? And if so, with the transmission in situ?

 

Thanx in advance

 

Avoid the obvious...

 

Pull the boot off again and shine a light up the shaft tunnel. If you can see oil on the bottom of the tunel, your leak is from the rear tranny seal. This is an easyish fix, with just the hassle of dropping the swingarm.

 

If there is no oil on the bottom of the shaft tunel then the oil is coming from the FD - a little oil goes a long way in the boot and the oil-level is still pretty high witha boot full of oil.

 

It is fairly common for the FD input seal to weep - very common in fact. This seal is abear to replace. The good news however, is that the weeping very rarely becomes more than just that - a weep. I found my oil loss stopped when I switched FD oil to a mineral oil-based 80W-90 weight GL5 oil.

 

My weep started with the bike under warranty and I had the seal changed (needs special tools and about 4 hours shop-time). Afer a few thousand miles it started to weep again. I had a total of three new seals under warranty. Then I just kept an eye on it and cleaned up the oil every now and then.

30,000 miles later I changed from synthetic to dino and the weep has stopped.

 

ANdy

[AndyS]

.....My weep started with the bike under warranty .... Afer a few thousand miles it started to weep again. ..... Then I just kept an eye on it and cleaned up the oil every now and then.

ANdy

 

Mine started leaking very early in life (about 3K).

It still weeps a little after alomost 50K. Keep an eye on it and I would suggest only tackle it if the bike is under warranty (they can have the hassle), or if the leak really starts to cause a problem.

 

Andy

[philbytx]

If the oil is clean (lighted/medium brown maybe but not dirty), don't sweat it too much. If it has never been opened before, this could have been in there for years. Had it happen to my R when I bought it..noticed the boot had a couple of ounces in it.

So I changed the tranny and diff oil and drained out the boot 2k miles ago and it is still dry.

[Linz]

I run different oil in the gearbox (Royal Purple 75/140) than I do in the FD (Shell straight 90W). The FD leaked badly when I ran anything else than straight 90W Dino oil.

 

A tech mod here suggested I change the oil to straight 90W (it's what is specified by BMW anyway) and I haven't had an issue since.

 

If the color of the oil in *my* boot was a reddish color, I'd know immediately that it was the rear tranny seal.

 

So, I have color coded oil leaks and smoother shifting. Win-win?

 

Linz