Here is a little update on this mess. I rebuilt the final drive (It needed an input shaft anyway.)and put it back on and the THUD is worse than ever,in every gear but it is constant. I think that it might be on the brake housing on the left side I drained the oil in the tranny last night and did not find anything but nice clean fresh oil.No flakes,no chunks,no teeth I even stuck a magnet in the housing and drug it around. Plus I strained the oil when I dumped it. It is a Thud not a knock. I'm gonna put the other combine to shelling corn today and remove the brake housings on this one and see what the heck I've got here. I also wondered if it was not the hydro coupler but I put the tranny in neutral and pushed full stick on the hydro both foward and reverse and it was bone quiet. it has the two speed hydro that looks like it weighs 300 pounds on it so I'm a little lerry of removing it by myself today but what do I have to lose at this point.