Re: Vribrations stop after pushing in the clutch
I had the same problem last year, but my jeep is pretty heavily modified. I'm running a chevy 350/nv4500/dana 300 combination. Not long after getting the jeep running after 3 years of work, my CJ would shake when the clutch pedal was let out (even out of gear), and smooth out when I pressed the pedal. Got under the jeep with it running and saw the trannsmission/adapter plate was pulling away from the bellhousing. I could actually see some of the attaching bolts through the gap. The bolts had pulled the threads out of the bellhousing.
Once I removed everything and made the necessary repairs, I looked at the geometry of the transmission and engine. I think that the transmission was installed too far up vertically and was causing a bind between it and the engine. I made some tranny/transfer case drops out of 2" steel. Now everything fits and looks more natural, and the vibrations have stopped, even at highway speeds. So far the bolts haven't backed out either.