My '93 C2500 6.5 diesel has had a problem of a clunk/thump from the right rear about half the time when I'm backing up and hit the brakes. Got under it and tugged/pulled/pried on all of the suspension. Nothing loose that I could find. But I noticed the isolator (or whatever you call them) between the topmost and next lower leaf in the right hand rear spring was displaced and appeared to be working/slipping. Also, the leaves were staggered like the shackle had come loose but the shackle was dead tight. The left rear spring had no evidence of this. I figure the leaves on the right rear are shifting and making the noise? If any of you guys have had this problem and sorted it out, I'd sure like to hear any advice. I read some good comments on these folks: Truck Parts & Trailer Parts - Pickup Truck & Trailer to Semi Truck I figure to replace them both, but thought I'd post this to see if anyone else had had the problem. Thanks for your time and any advice.