don't know where this would go.
 

When I put my auto. trans. 80 280ZX 2+2 into 1st, 2nd, drive, or reverse, there is a loud clunk from the rear end, it's been there for a while. My dad said maybe it's my U=jionts going, but it feels like the back of the car drops down when this clunk accures. Anyone know what the hell this is? :confused: :confused: :confused: :confused:

Is it when you put it in gear, or just when you start driving. If it's when you put it in gear, it's probably a busted mount either on your diff or trans. Your U-joints could cause a clunk, but most likely you wouldn't notice it like you explained unless you actually put the car into motion.

Make sure your diff mount is still intact and not loose. Might as well check those U-joints for play while you're down there too.

I had that probelm--felt like the whole back end of the car was coming up into the back when I put it in reverse. It was the transmission mount.

I had a similiar problem on my '81. It was my u-joints. Because when I got above 35 or so. It would clunk going down the road! :eek:

My Rx7 has this problem. Seems its a rather large gap between the differential 'moustache' mount, and the body mount. There's a crown bushing on this particular setup that sagged and wore out over time, and under 2000rpm in anything above first gear, it knocks back and forth - it actually creates more bass than my 10" sub! Not good ... I'm looking to replace that this summer.

it is when i put it in gear, not when i start moving. I'll check those mounts, (mutters, son of a ...)

where can I get the mounts and how much?
is it a do it yourself type thing?
is there anyone who could walk me through it, etc.?
Thanks guys!

Pretty sure you can get them from MSA or Victoria British, Nissan, maybe even a parts store like Autozone, not sure though.

If you got a floor jack and hand tools. You can do this yourself no problem. Much easier than engine mounts. If you need help just ask when you get the parts.

Did your mount end up being bad?

didn't look yet, but I want to be prepared for the worst when I do.