ok i have a 1990 cherokee lifted 5.5 inches on 32's. recently had my motor mounts replaced since i was hearing the typical thud from the front end when i would accelerate hard etc. everything seemed to be fine but sometimes when im turning into a parking space i will fell/hear that thud again! also at times even when im on the freeway and i punch it i will fell a slight kind of thumpp thump thump....i dont know what it could be everything seems to like fine.

 

check your tranny mount... and u joints