Metal on metal sound from the rear... on 2000 GMC Yukon Denali

If I take off hard, stop suddenly (even from idle speeds) and if hit speed bumps faster than I should, I can usually hear some kind of noise from the rear of my vehicle. It sounds like metal on metal. Not a grinding sound or clanking, just a single sound (a single clank, maybe). Like if you were to hit the exhaust pipe with a tool while under your vehicle I guess is the easiest way to describe it.

I replaced the shocks, as I noticed the rear would sag a bit when taking off. But that didn't fix the problem.

Ive heard tons of suggestions, but its just people guessing off the top of their head. Has anyone had this before? Or any suggestions?

Asked by for the 2000 GMC Yukon Denali
I would guess that you have either a broken or loose suspension component. Or just like you said it sounded, a looses exhaust hitting somewhere on the frame or under body. Crawl under there and start wiggling and hitting things until you duplicate the noise.
Ive tried looking for anything loose that could move or bang into something else and make the noise. But had no luck in finding anything. And I cant really tell if something is out of whack, because I don't really know a lot about the under-side of the vehicle. Meaning I would've recognize if something didn't look right unless it was obviously broken. I don't spend much time under vehicles.

But I cant pin-point the sound's exact location, because to do so would mean Id have to lay under the vehicle, and have someone take off kinda hard, but that doesn't sound very safe lol

What would be some specific parts to check out? I can try to familiarize myself with a few parts at a time and get under there and see how it looks compared to my parts.
Try this if you can, have some one jump up and down on the rear bumper while you listen. Pay particular attention to shock mounts, spring mounts, sway / control bars, and anything else that moves up and down with the body of the truck. I have found exhaust clearance problems just by kicking the tailpipe upwards, use steel toe boots if you can, very painful in tennis shoes, don't ask, and yes I tried it ONCE. I could even be motor or transmission mounts. I can't be real specific since I am not there listening with you, sorry.