Had a 86 model JD 850 in here last week that was grinding bad whenever you put it in gear. I split it to replace the clutch and throw out bearing. The main disc was in 2 pieces, the lining had came loose from the rivets, the pilot bearing was gone except for the outer ring and the pressure plate had some broke springs. I didn't take the plate apart but just looking at it the pto disc looked good. The flywheel was flat with no burn spots, I put a new pilot bearing, disc, pressure plate and throw-out bearing in it and then back together. It still grinds going into any gear whenever you start off from neutral. I've got about a inch of free play in the pedal, when releasing the clutch it will first engage the pto then the transmission, works like its supposed to. Don't understand the reason for all the grinding.