When am driving at any speed I hear a thump or thud in the rear only. Anybody have any idea what it might be?

A lot of possibilities, but there have been a fair number of reports of worn-out rear stabilizer bar bushings. If you can get the bolts out, it's a relatively inexpensive DIY job.

Other possibilities - broken trailing arm, shock or exhaust hanger.

ended up being the rear end bushings. but some how amongst the repair they got my exhaust to rub against the sway bar. They corrected that to only have it rub against the body. Going to exhaust shop soon to re route the pipe.

glad you found your problem.
i had a clank from the rear part of the e. adjusted spair tire/jack, still clanking, took out spare tire/jack, still clanking. checked suspension as others said to do, couldn't find any issues, still clanking. by now it's starting to drive me crazy so i checked suspension again, nothing seems wrong, reached up and tapped the exhaust and it moved like a swing. replaced rubber hangers at a total cost of 14 bucks (they were all stretched out) no more clank !