When I had the lower body under tray off a couple of months ago, I found all sorts of detritus, amongst it was a sheared tapered pin that I assumed was from some long repaired mishap before my ownership…wrong.
The front input flange on the gearbox is located by a keyed taper and secured by a tapered pin which is a rather odd way of doing it when a big nut would have been much nicer. The pin had sheared and fallen out (although the nut end remained) the flange moved forward allowing the the keys to wriggle half out of there slots destroying the oil seal and so it gradually ratcheted toward the clutch taking up all clearance.
The way to fix this was brute force with a No.3 Thor, eventually the cotton reel was persuaded to to move out and thus the clutch assembly is now on the bench. I’m just hoping the taper isn’t completely buggered but that is what winter is for …isn’t it?