Hard Shifts, Slippage before lockup

All Symptoms pointing toward The PCS Selonoid, I will tear into it soon enough but the question is what Has to be taken out of the way?? I am wondering if the CV Shaft has to come out, according to the buick forum that is the case on the cars, but this is a van.... Does anyone know if this "PCS" will fix the slippage "flutter" between gears. I have do major engine work usually myself but never touched a tranny..... not too scared to try though.