I dissassembled the 12 bolt from my 66 SS396. It needs just about everything. The axles are worn (had those quick fix bearings), the spiders seem to bind up in one spot, However the ring & pinion are in great shape. I plan on buying an eaton posi, 3.37 gears, axles, and a complete installation kit from tomsdifferentials. Has anyone ever purchased from here? if so I would like to hear your experiences. When I took the open carrier out there was only one shim on each side, and I was able to force it out by hand, did not need a pry bar, does this sound right? Also, there was no pinion shims, should there be any? I assume the shiming was correct, because the carrier did not make any noise, and the wear on the gears is perfect. The cause of the binding in the spiders seems to be from the cross shaft, it's hard to get in & out. I've just about rebuilt anything a car has to offer, but never a rearend, any advise is appreciated. I know most of you might say to take it somewhere and have a pro do it, but I know I can handle it. I just don't have any tricks or tips on how to do it.