1989 r100gs changed out the tranny, rear-diff, and motor oils today. when i got done, i wanted to run it a bit to settle everything to see if i needed a top-off. I put the bike in 1st gear on the center stand, leaned on the bars to raise the rear wheel, and let the clutch out. it made a strange clunk-clunk-clunk noise as the rear wheel went around. so i pulled the clutch in, and put it in neutral. while in neutral, and idling with clutch lever pulled in, it sounded fine, but when i released the clutch, (still in neutral) it didn't sound so smooth, but sounded like something was rattling around... not loose rattling around, but like the pilot bearing in a tranny in a car with high mileage. anyway, i was starting to panic, but i got on the bike and rode it down the street and back. NO NOISE NO CLUNK! what's going on????????? ps. ther's a little rubber cover on the clutch shaft sticking out the back of the tranny. is it just a dust/h2o protector or does it actually hold in tranny fluid. i ask because it was a tad bit gooey and if it serves as a seal, i wanna get it replaced before i lose all my gear oil.