Well with a little more info/facts as to what you have, and have changed out,....adding a hyd. throwout bearing, do you know what your "stack"(hyd TOB) assy height is compressed and static?, and what is required for your application,....most hyd TOB assys, unless designed for your application, usually need to be shimmed for location, so that they don't cause interference fit problems, or lack of proper disengagement,.....who's hyd set up are you using?....is it a true hyd TOB?, or are you using a slave cyl. to activate the mechanical fork?.......