Slack in the Diff
 

So I figured this sub has experience with diffs. So I have some clunking in the rear. In my TURBO FC.

ITS NOT THE FRONT DIFF MOUNT. ITS NOT THE FRONT DIFF MOUNT. IT IS NOT THE FRONT DIFF MOUNT.

I have replaced the FRONT DIFF MOUNT with the Solid PBM unit and I had the mounting tab reinforced so it wouldnt break. I have Delrin diff bushings and the PBM toe links. Stock toe arms and Camber link.

When I jack up the rear and rotate the wheel forward and reverse the joints dont seem to slack and the wheels move together its inside the diff it clunks. When Im driving on and off load I feel the slack and hear the clunk. The diff locks up hard still and I dont hear any odd noise when driving. Its been like this for a while and I now have to funds to address it.

My only other deal is that I dont know what brand of diff is in there. I dont think its stock. To me it locks to hard to be stock, but honestly I dont know. Also its my daily so I cant just pull it out on a whim and find out.

Any suggestions as to how to fix, what the problem is. Anything at all.

Have you done the pinion snubber mod? I have the Mazdatrix comp mount in my car, and added the snubber and it's a night and day difference.

Aftermarket diffs will make noise locking and unlocking(like taking turns). Is it doing this just going in a straight line?

It clunks when im on and off load. Doesnt make any locking sounds in particular, for example if I were making a turn and where to mash the throttle it wouldnt clunk but if I were to be going and engine brake and mash the the throttle it will clunk.

It has all the symptoms of a typical broken diff mount but its not the mount its in the diff.

Maybe a bad ujoint in your driveshaft?

Its not the driveshaft.

Maybe I should say there is play in the diff that is causing the sound.

ring and pinion needs adjusting or replacement. Mines doing the same thing.

This may or may not be your problem, but what about your halfshafts?

Half shafts are good.

If its the ring and pinion, do I have to get new gear set?