International 8600 Clutch very grabby, what could it be?

Most expensive part doing it yourself would be the rear main installation tool group. Renting from someone would be your best bet.

 

YouTube video by Gordon Roberson, he puts one in without an installer. I’ve known of a few others that had to have seal re done, and wonder if that’s why. Rear cover is a job, I can handle it, lot of labor time on that I’m guessing. Biggest hurdle is transmission jack. Harbor freight one gets mixed reviews. Looks flimsy. Renting one if possible, but probably turn into a 4 day deal, Lol. Not sure I can do the clutch myself. Did one yrs ago on a 67 Plymouth by myself, got pinned under trans, Lol. I’d hate to drop 800 lbs. trans. Different beast

 

Check local equipmen/ tool rental places. I rented one before pretty cheaply and it was decent one.

 

Possible Rear main seal leak. Oil on the disk will actually cause it to bite and not allow it to slip. It's funny how it reacts that way but it's happened to me before on a caterpillar