Ok,..I recently purchased a 1972 240Z that has been sitting for several years w/o running. I've got it up and running great, except I have a hard "clunk" at shift points coming from the right rear.

Would this most likely just be a bad U-Joint on the axle or could it possibly be the differential mounts?

Any help would be appreciated,

Danny

In order of likelihood, I'd say front diff mount, mustache bar bushings, driveshaft U joint, and then halfshaft U joint.

in order of ease to fix I would say haft shaft u joints, drive shaft u joints (depending on the year), diff mount (well this actually is really easy tied for second if you use the new mount and dump the strap) then mustache bushings ( I have not done this yet on my car because it looks like a pain in the a$$).