R100R driveshaft boot/transmission seal

[deersemaj]

I have noticed oil on the right hand side of the frame, near the rubber boot between the transmission and the driveshaft (which does have a small tear and will need to be replaced). My understanding is that my driveshaft is dry, so any oil there must be coming from the transmission, past the output shaft seal. It looks like I need to disconnect the driveshaft, remove the transmission,and remove the output flange. I can't tell from drawings, either the fische or the BMW repair manual, which side the seal is pressed in. I'm assuming from the driveshaft side, based on the springy side of the seal facing rearward. If so, it seems that I could replace the seal without removing the transmission cover, and if not I would need to remove the cover.

Am I on the right track?

Is there a way to check the transmission oil level? I know most auto manual transmissions are filled until oil seeps out of the fill hole on the side, but all I've ever seen in my repair manual references filling by volume. It would be nice to be able to just keep an eye on the level until I have a chance to make the repair.

Thanks in advance...

[Deleted User 62]

It looks like you're in luck, according to the MaxBMW fiche the seal is installed from outside of transmission. see this discussion: viewtopic.php?f=1&t=6368

[Kurt in S.A.]

If the driveshaft is indeed dry (I can't remember which years those were), then the oil can come from two places. The transmission oil is usually filled to the top of the threads on the lower left hole...I've never filled my /7 by volume. Same with the final drive, although IIRC some of the later drives have fill holes different than the /7 (my only reference point).

Removing the tranny output flange is a biyotch...requires a special tool to break the torque.

Is the speedo cable bolt center hole plugged? It's supposed to be open to let the tranny breathe. If not, expansion could be forcing the oil out. And at one point, the v-notch at the top of the output seal was closed...again, I forget which years this was done for.

Kurt in S.A.

[Deleted User 62]

I can't tell from drawings, either the fische or the BMW repair manual, which side the seal is pressed in. I'm assuming from the driveshaft side, based on the springy side of the seal facing rearward.

James, I assume we are talking about your R100R, yes? If so, there should be no "springy side", the seals are different, and they install from the outside/rear of the transmission with what would be the spring side of the earlier style seal facing forward (front of the bike).

[deersemaj]

James, I assume we are talking about your R100R, yes? If so, there should be no "springy side", the seals are different, and they install from the outside/rear of the transmission with what would be the spring side of the earlier style seal facing forward (front of the bike).

Thanks Tim. We are. I've seen a picture now (I haven't ordered any parts as of yet), so that helps clear it up.

Will I have to remove the transmission for this job, or is there enough room to remove the output flange to gain access to the seal and replace it? I feel like I might as well remove it. I don't know when the splines were lubed last, what the clutch parts look like, etc. And I need to replace the neutral switch, so it probably makes sense to get it all done at once. Is there anything else I shold think about looking at/replacing while I'm in there?

[Deleted User 62]

Yes, the transmission must come out. Is there any gear oil on the shelf under the transmission? It smells like sulfur. If so, you may want to consider changing the input seal while you're in there. Also, you should remove the clutch lever and rubber boot before pulling the transmission, there is a spring under the boot that pushes the whole assembly forward and will make it hang in the clutch when you're trying to pull it out: Lastly, an easy way to disconnect the neutral switch, wait until the transmission is loose and pull the wires off as you lift it out of the frame. Installation is the reverse of this procedure...

[Deleted User 287]

Removing the tranny output flange is a biyotch...requires a special tool to break the torque.
Kurt in S.A.

[deersemaj]

So I ordered all of my parts to replace the seal and the neutral switch. When I got the transmission off of the bike, I turned the output shaft by hand; not good. It was notchy and felt as if there was gravel in the box. Maybe a bit oEif an exaggeration, but clearly not right. I took it to a local shop to have them help me get the flange off, he didn't like it either and said it was probably the front bearing on the output shaft. He popped the cover off, and sure enough it was clear that was the culprit bearing. Also, no circlip (1994, not sure of the transmission number, its still at the shop). It also appeared that water had been in the transmisssion; there was bad pitting on the helical gears.

I know BMW doesn't seel the intermediate shaft gears, only the complete shaft, but I know they are available from some places, Motobins being one. Either way, it looks like it's going to add up quickly. Right now they have it, and are preparing me a quote, but I'm not sure what route I'll take. I could let them do it, take it to Anton, or buy the shafts and bearings myself and assemble it. I've read as many of the posts here as I can find, and it doesn't look too bad. Any thoughts would be appreciated.

[enigmaT120]

For a second I wondered why somebody had a nice Shoei helmet on his work table. Doh!

[deersemaj]

I'm still waiting on hearing from the shop that has my transmission; they are supposed to be working on a few different options for me. Everytime I go to Max BMW's fische and start adding things up, it looks expensive due to the damaged gears. This leaves me wondering about a rebuilt unit. I looked at Motobins and Motoworks, and they both offer refurbished gearboxes for what seems to be a good price. Of course, neither one of them ships them to the US. I've heard of places that will accept a shipment and forward it for you, but I have no idea how to go about doing that. Does anyone have any insight? Also, is there a place here that offers rebuilt units? I know I could ship mine to one of many shops, but for time reasons I would like to find a place that could ship one off of a shelf...