Installed these poly bushings in my leafs and shackles, be prepared to do some work to get your old bushings out, I used a my ball joint press to push the OEM inner bushing sleeves out, then I walked the rubber bushings out with a drill bit and then cut the outer bushing shells and hammered them out, install the new bushings on one side following the directions and I like to fill the air gape between the bushings with Lucas red and tacky before hammering the center sleeves, it gives the bushings a little extra grease and I have never had issues using it on poly bushings, I have done this before and its time consuming but its worth the ride quality afterwards, my OEM bushings were shot, I also did my front lower control arm bushings, my suspension feels more controlled now and my alignment returned to spec in the front along with ride height overall, also look in replacing your rear body mount bushings with the GM hydro bushing update for your older GM truck if your getting poor ride quality and frame beaming, I replaced my front control arm bushings one weekend and the ride improved, the next weekend the leaf and shackle bushings and ride got even better, then the hydro cab mount update from GM and it rides as good as its gona get for a 3/4 ton truck, I have a 2006 Duramax 4x4 CCSB with a BDS 4.5 lift kit, Bilstein shocks, Krypotonite upper control arms, steering and front lower bump stops, 295/70r17 AT tires inflated to 60psi at all times and rear air tow bags that have 10+ psi in them at all times, I do lots of towing and driving overall and im happy with these bushings.

Just want to say, I had purchased this with a front and rear bushing kit (energy polyurethane) as well. I also bought their torsion tool, upgraded ball joints, and the moog upper control arms. All this for my 05 duramax. I bought new shocks (ranchos) and outer tie ends somewhere else. But, now my truck rides awesome! I immediately took it offroad in the az desert and it did well. Going down the road, everything feels solid. I greatly enjoy my truck in a different light now. And the only reason why I did such a major project (I did this all myself) is because my duramax needed it. Bushings were cracked, blown shock, ball joints leaked grease, etc. I wanted to feel confident that my suspension would be overbuilt, thus increasing reliability. Very Happy!