Sounds like my muffler is banging on the floorboards when I go over any bump. So I took it to a muffler shop and they put it on a lift and the exhaust is tight. We began wiggling stuff but could not duplicate the thunk. The car has welded subframes and they look good. The car drives just fine except for the thunk.

 

Do you have longtube headers?

 

i think mine does the same thing...only when launching or taking a turn kinda fast. i think its just the pipes bouncing around even though im pretty sure theyre tight.

 

if its under suspension articulation, u might wanna check your rear bushings to see if a control arm bushing or mount has gone bad

 

How do I check to see if the rear bushing are bad?

 

just jack up the rear end and start looking for most of the pivot points, signs of a weak or broken bushing include flaking, cracks in the bushing, it being odd-shaped (ovals, pinched, deformed)...you may want to take a wheel off and check the spring isolators (bushings at the top of the spring) i got to replace one of mine myself[>:]

my dads explorer had a bushing go bad on his front control arm, when u go over the bump, does the CLUNK happen when the suspension is supposed to be coming down? if so then its probably a bushing

 

yeah mine does it too, its right where the exhaust goes over the axel, at that hump, it swings and hits the metal there. i guess you could try wrapping it in exhaust tape to cushion it so u can't hear the metal on metal

 

rear bushings, shock bolts, and tail pipes is what i would check. mine did the same and it was the tailpipes hittin the frame above the axle.

 

Thanks, I will check it out this weekend!