My Ford 850 has a smaller diameter pto shaft than most newer tractors I believe. When I purchased it last spring I also bought a mower with it. The guys there hooked it all up and used an adapter on the shaft with a "roll pin"? Well somehow I managed to wrench that adapter enough hitting a rock or something (I'd imagine) that it twisted it up in the middle and sheered some of the grooves. Obviously I need to replace it, and I was reading that the best way to remove the pin is with a punch and hammer? I'm just seeking advice on what precautions I need to be taking to not damage the actual pto shaft, and how careful I really need to be. Are these adapters designed to shear before the pto shaft gets wrecked? I think I was reading a while ago that its not a good idea to run tillers on these tractors? Or maybe just not with an adapter. What else can I do? (besides not hitting rocks)