So I don't think they are air shocks, they look as old and dirty as the rest of the underside which makes me think that they are stock oil shocks. I did notice on teh left exhaust pipe, kind of over the diff, that there was a shiney quarter-sized area that looks like it could have been scraped so maybe that is it. I need to get four guys to sit in my car so that I can look underneathe it. Is it possible that the rear tires slam the wheel well going over a bump? I'll keep you guys posted as I discover things.

 

I had that happen to me as well and it was my exhaust pipe hitting the axle (right where the break lines T to go to each wheel, and there is that bleeder valve). I had to loosen my exhaust and adjust it around to get it to not hit (but now its to close to the break lines)

Edit: I also had developed a small dent in the exhaust pipe so you could also check that.