[wafrederick]

You do not have to rebuild,just do a repair replacing the sunshell.The upgraded sunshells do break and I know one transmission shop that can prove this,they have seen them broken.While inside,remove the snap ring for the steel for the clutches in the direct drum and look for 5 black springs.If you see them,remove them and throw them away.The aftermarket says to throw them away and GM says to put them back in.The problem with those 5 black springs is that they restrict the clutches from floating and burns them right up.