Ok, I know I've seen this on here somewhere, but I can't find it.

After replacing my rear shocks a few months ago I have this weird "clunk" that comes from the back of the car when I let off the gas. It also happens when I hit the brakes with the clutch pushed in. Also happens when I downshift, or hit another gear pretty hard.

The drive shaft universal is nice and tight...first thing I checked. I know I got everything back together and tightened to spec. Could some mount be loose under there that I didn't touch?

 

Sounds like differential mount gone bad.

 

i had my universal go out when i had the clunk. to properly check a universal, the shaft must be removed and slack taken off the joint. the diff mount usually only clunks when you accel or change gears, not so much under the other times, like when you hit the brakes

 

I have to agree, had exact same issues on my 77 280z, and it was the Mounts and the rest of the Bushings in the rear were looking sad, when the bushings loosen up , things slip, things clunk.

http://www.thezstore.com/page/TZS/PR...C06A/23-4100AZ

maybe more than you need, but I bet it would ride and handle like a dream after a kit like this, on my 77 I used http://www.thezstore.com/page/TZS/PROD/PSDC06D/23-4139
and a few other parts to take that movement out, really made the car feel new again.

In the last month or so, I've noticed a few squeaks and little clunks in my rear end, so I'm going to do a full kit on my 84 300ZX na, Ill post back with the results and some pics.

 

You know what? I got a complete urethane bushing kit with my shocks and have a few things that I couldn't figure out where the hell they went. I may have some for the differential. Gotta go crack open the box and look.

 

I'm having the same clunking in the back when taking off. So was it the Universal Joint?