Nutbuster, There is a tab on the bottom of the clutch pedal that hits the platform that you put your feet on when driving the tractor. when this tab is 1&quot; away from the platform the shaft should turn freely and not before. When you depress the pedal is there any free play before you can feel increased resistance? If the clutch is not adjusted like this you will have the problem you are complaining about. been there  done that. Try adjusting it like I say and see what happens, Chuck      Go over to the Oliver forum on yesterday's tractor and post your question. I can post a picture there but not here.
I think the throw out bearing is pushing the pressure plate fingers so far forward that they are hitting the clutch plate causing it to spin when fully depressed. Start the tractor and drive it a little in say 4th gear just above idle, then slowly push the clutch in till the tractor stops ( probably about half way down) then push it down all the way and notice if the tractor tries to move.