I will be trying this on my Truck this weekend. From the postings, the clamps seem to help/work. I'm sure after 235,000 miles my rear springs are weak. It must be axle wrap.
I have been living with the GM clunk for years with my 1990 Silverado. I tried this leaf spring clamp suggestion and low and behold it works! My truck is completely stock so not sure if this will work with a truck that has been modified. Such a relief!would have never believed it myself, but I've just installed a couple of "leaf spring clamps"(approx $15/pr) on my rear leafs, ahead of the rear axle, and my clunk is "all but gone"......can make it clunk slightly if I try, but driving normally, its GONE... cant guarantee it will work for everyone, but my truck has low miles & in excellent condition, and has been "clunking" almost since day one. IMO, these 1500 trucks have wimpy rear leafs & axle wrap is the problem, so anyway you can lessen(or eliminate) the "wrap", the less "clunk" you'll experience.(fyi, my clamps are 4" from the axle, but I would say 4"-6" would do the trick)