A complete novice trying to solve oil leaking around transmission and paralever R100R



I've owned this 1993 R100R for quite a while, over 20 years now and have done most of what little maintenance that it's needed myself; engine trans, final drive oils every year, tires, brake fluid, etc. For a while I'd noticed slight wetness around a sensor plug under the transmission but never enough to drip. More recently (not long after I last changed fluids) I noticed drops of oil on the floor and in checking found oil at the outside bottom of both driveshaft boots. Today I decided to take a closer look. After removing the collector I had access to the sensor bolt figuring I'll have to order a new one but it wasn't very tight. It's threaded into the aluminum case so I wouldn't want to use much force but I was easily able to snug it up almost 1/4 turn so maybe that'll solve the oil in that area.

Next I loosen the front driveshaft boot and a bit of oil comes out maybe a thimble full but I don't believe there should be any.

Then I pull the rear boot and OMG probably 6 ounces of dark oil pours out! No wonder there were oil drops on the floor, there should not be oil in the paralever at all should there?

After cleaning up that mess I check FD and trans oil levels and they're right at the bottom of the threads.

So just sitting here trying to determine where all that oil came from, maybe it was me over filling the transmission over the years? The fact it is so dark is likely because I used to add Moly Gear-guard to the trans and FD with each oil change. Tom Cutter noticed that when he had the transmission out and said not to use moly so since then I haven't.
So some of that oil almost had to be from prior years. My fill procedure for the transmission was once up to the threads, give the bottle another good squeeze then quickly screw the plug in. Does the transmission vent or overflow to the paralever? If so my overfilling over the years could be my problem. Or is the only way oil could get in the paralever is past a leaking seal? For now the boots are pulled back so any residual oil can drip out.

I have since discovered that the transmission vents through the speedometer cable bolt, and there is no oil present there. Looks like the output seal is the culprit, now to find someone to change it......