"Clunk" in rear end upon acceleration

There is a pretty noticeable clunk sound coming from the rear end the second I start . It feels like the rear end is shifting to the left or right. It even happens when reversing the moment I start out. Keep in mind this only happens as soon as take off, then it stops. Almost like a real apparent suspension pre-load is happening. When I slow down for a stop sign and then take off again, it happens once again.

The last time this happened all it was was a lose sway bar; so I tightened those up and no problem from there on. This time all the bolts are tight including upper and lower control arm bolts. I did however notice about 1/4" of play in the driveshaft. So I called the guy who did my gears a couple years ago and he said it was normal to have a little bit of play in there.

I also looked at the torque boxes and it doesn't look like there is any apparent damage to them.

Anybody have any suggestion or had any similar experiences?

Thanks.

I've been reading previous post on this issue and it seems pretty common that the diff UCA bushings could be shot. I guess I'll check that tomorrow.

How do you tell if the U-joint is bad?

It turned out to be bolts. I'll tell ya, if those control arm bolts aren't hammered down to a pulp, my arms don't like 'em. So, I found out that my jack is multipurpose. I took off the handle and used it for more leverage on the bolts and cranked those SOB's down! No more clunking.

Thanks for your help guys. I'll be putting in a Tremec 3550 pretty soons and going back to the track for some better times (hopefully).