Clunking/knocking sound from rear

[JustinSwampthingjku]

The past several times I've been light wheeling I've been hearing a clunk or knock sound from what sounds like the passenger rear quarter. It almost sounds like I'm bottoming out or hitting bumpstop but the sound happens on very minor stuff, just driving down the trail. But I haven't noticed the sound at all during daily driving like going over speed bumps or something. I cant see anything making any interference or hitting. I have about a 5in lift and 35in tires and definitely aren't hitting bumpstop just driving down a bumpy trail but that really what it sounds like. Could I possibly get some recommendations for things to check or areas to pay attention too? With out seeing any signs of interference or hitting, I'm really not sure where to start.

 

[WIJeeper]

I just found my clunk after three days of looking for everything. Loose bolts, rubs, and such. I ended up having my wife drive while I had the doors off and everything cleaned out of the back including spare tire. We are driving down the road and i am leaning out the passenger side waiting for a bump. We hit some bumps and I heard the noise and noticed the after-market rear bumper touching the tub body. Yeah! Back to the shop and loosened the bolts and move the bumper down maybe an 1/8". Another test drive and so happy! Picture after adjustment.