loud clunk from rear axle

My '05 Ranger Edge has started making a loud bang from the rear axle. It does it when I apply throttle, apply brake, and to a lesser extent, when I hit a (small) bump. The truck shakes when it bumps almost as if I got rear-ended. What does this sound like?

I forgot to mention that I feel it "bounce" some when I ride the brakes.

I found my problem. Front brake caliper floating loose. Bolts fell out.

Funny how a sound you are sure from inside is from the rear is actually from the front, or left is right and vice versa.
Reading your first post I'd have thought it was a spring shackle, then I read further.

I would have thought it was a shifty axle or similar too. Glad now I went with the smaller steel rims, or i would probably be SOL.