Leaking shifter shaft seal

[bobo1167]

So I've got more oil on my boot.

Earlier this week in the morning I noticed oil on my boot toe and found the shifter shaft seal leaking, again. I figured the past occurences were fixed during the process of two trans rebuilds in the last three years.

I shoved in a new seal this morning, with 90W leaking all over the place. I lost a lot less oil that way, than draining the trans properly. Cleaned up the mess and I thought I was good to go.

This evening the 15 mile test drive proved me wrong. I got home with a nice new smear of 90W on the frame tube, again.

The shaft itself didn't seem to be worn, it looked like new.

Does anyone have a suggestion for the next step, I'm outta ideas.

thanks bobo

[Guzzi]

I just replaced the same seal on my '83 R80RT. I drained the transmission cuz it was time for new lube anyway. this allowed me to clean up and examine all parts involved. One important thing is to make sure not to score the outer sealing surface when removing the old seal. Closely examine the circumference (sp?) of the leading edge of the shaft that goes through the seal. Often, that surface will develop burrs and harm the seal upon insertion. Put the new seal in DRY with a DRY outer sealing surface also. Tap it home with an appropriate size socket. Hope this helps.

[bobo1167]

Guzzi thanks for the ideas. I did a much better job of cleaning up the mess and installing another seal last nite. I even used BMW label 90W oil. That didn't fix it.

So wouldn't you know, this morning I made an effort to get into the sunshine and looked much harder. The oil on the shifter shaft boss was being blown back from the oil pressure sender. The hot oil would blown off the leaky oil sender cleanly and that part always has looked clean. I ran the engine while watching the oil sender and it took a few minutes but, yahoo!!, drip, driip drip, it is the real problem.

Back to the dealer, again.

thanks bobo

[barryg]

bobo 1167 The way to stop the leaking shifter seal may be to approach the problem from adifferent angle. I believe that the transmission you have holds 800cc of gear oil. That level puts it above the seal. Try using 700cc, which will put the level below the seal. I had the same problem on my 74 R90/6, after 30,000
miles and no leaks, I think I solved my problem. Good Luck

[flash412]

I had a 5-speed box that went through two seals in quick succession. I don't recall the ID. But replacing the seal with one that had a 1mm smaller ID cured my problem.

[bobo1167]

Thanks all but the problem was the oil pressure sender, not the shifter shaft.

The wind blew the engine oil back off the oil sender and it would collect and drip from the shifter boss casting thingy. The shifter was a red herring, I was fooled.

thanks bobo

[BMWRich58]

I just did my seal on a '92 GS with 40K. After removing the seal, I took emory cloth (very, very fine sand paper) and "lightly wiped"or sanded the internal sealing surfaces
(seal hole) in the trans housing,and also the shifter shaft. Both felt/looked "rough" to the touch.
I then "lightly" lubed the seal with trans oil before installation I'm glad to report "Leak Fixed"!!

[Weasel]

What year is your bike? Mine is a '75 R/60/6. It leaked from day one ( I bought it new). It never stopped leaking. Mostly it weeps, then when it gets bad enough, I have the seal replaced. are you applying a bit of oil on the seal before installing? I've heard about inspecting the shift shaft itself for burrs and wet sanding to remove same...but I've never bothered...it shouldn't gush out like that...are you sure you have the right size seal?