Thump in the night & DAY !!

1992 xj stock nothing crazy , new exhaust , new monroe Sensa-trac shocks , but on normal highway driving I get a thump when hitting any kind road break , almost like a muffler hitting the under carriage .. Not the spare tire that squeeks and have removed it to resolve that .. Have had on lift and rattled and shacked everything possible but still get THUMP !!! Not rear hatch have driven down the road with thet opened as crazy as it might seem .. ( didn't say I wasn't crazy but the thump has got me and getting that way ???)
Thanks for what help you can offer ...
THUMP !!!!!!
Geepers

check to see if your tranny mount is toast if it is itll sag and cause the exhaust down pipe to smack the crossmember just get underneath and push up and down more than a 1/4" of movement and replace it you should do all three at once(tranny plus each motor mount)....
luck
themud
:wave:

I have the same problem and have narrowed it down to the track bar. I used to be lifted, I think that is what did it in...
~Joe~ just my .02

Try this: get it out on the driveway and jump up and down on the rear bumper (carefull not to slip) and listen for the sound. If you still get it, pull the rear shocks off and listen for the sound again. I had some ProComp ES3000's that died in about 4 months from the time they were installed and they generated a noice like you describe.

If jumping on the rear doesn't generate the noise, pull the shocks off anyways and compress them by hand and see if they feel smooth while compressing or uncompressing, or do they do so in a "jerking" manner. Mine had the beginnings of that (that's what confirmed it for me after the jumping tests).