Transmission clunk

91 Cherokee limited 4.0 automatic. recently acquired it in a trade and it hasn't been taken care of. trying to work an issue out. when driving at any speed (in 2h) if you let off the throttle without applying the brakes there is a clunk that you can feel that is coming from around the xfer case or the transmission area, it feels like something is slipping or engaging not sure. like its engaging 4wd momentarily. it is very random on when it does it but will happen for about 5 min and go away and temp doesn't matter. it gets a lot worse during and after going over bumps. the 4wd linkage seems a bit loose and im checking into that but was wondering if anybody else had seen this issue. makes for a scary ride sometimes. have checked and filled fluids in trans, xfer case, and both dif cases and still does it.

First, check your engine mounts and the bolts that hold the engine mount brackets to the engine block. Next, check the transmission mount.

Post up what you find.

just changed the trans mount last weekend, engine mounts look like they need changed. also when this happens my speedometer cuts out. was just messing with it and if i shift it into 4wd and back into 2wd my spedo will come back.

well found the problem, there is a crack in the back of the transfer case.

That will do it.