Need thoughts on my DD Tahoe issue

About 4 days ago slowing down for a stop sign a loud noise started. A noise like I blew a tire and the tread was flapping. Stopped, check tires, inner fenders, etc nothing wrong. Continued on my way no issues. Figured maybe something in the road I somehow didn't see.

2 days later, same noise doing about 55mph. Slowed down and it stopped. Figured I'd pull wheels and check brakes. Well, didn't get to it last night.

Today 75 down interstate and I thought something was going to fly through the floor. Slowed down it stopped, I made it to work. I'm going to drive my truck tomorrow until I can check it out closer. Visually, I see nothing wrong.

Any ideas for what I definitely want to look at? Front hub bearings? Anything else? I can't tell if it's from the front or back. Seems like back though.

2006 Tahoe Z71 with 5.3. All stock.

Motor mounts and or tranny mount causing the driveline to hit the floorboard?

Re:

Pinion bearings

Pull the diff cover, limited slip carrier pooped do death?

Thanks guys. I'll check all those. I despise sporadic issues like this. Hardly ever easy to find.

Does a Tahoe have a carrier bearing? That's a possibility

Also check the bushings on the torsion bar crossmember. The ones in my work truck are shot and over rough pavement it sounds like someone is beating on the floor with a hammer.

Wonder if the stupid encoder motor or transfer case module is trying to throw it in low range. Look at the plastic splash shield under the front, behind the bumper, they break all the time, maybe catching wind and flapping.

I bet you lost a caliper bolt

Well, this dropped out of the rear rotor/drum when I took them off last night. Not sure where the rest is, but I am hoping the material being gone caused enough play for the steel shoe/ring thing to occasionally move and make this noise I was hearing. Going to get parts at lunch today and drive it tomorrow with fingers crossed. I checked all the caliper bolts, hubs, bearings, mounts, etc. I was about to drop the rear diff cover when I found this shoe.