Ok, I have this re-occuring problem on my pickup, 22R,5spd,1pce rear d.shaft. About a year ago I had the same problem, lots of clutch chatter after about a half hour of driving. I replaced the clutch, machined the flywheel and put in a new rear main seal(was leaking a bit). It was good for a few months then it started to happen again. I do have some oil coming down the back of the engine and coming out at the bottom of the tranny. Anyone have any sugestions? Is the oil leak the cause? If I fixed the leak would I have to replace the clutch again? The tranny mount looks fine, but could it be that instead? I'm getting tired of pulling the tranny out once a year or less. Anyone had anything similar? thanks for your help.