bought a 421 oliver sickle mower awhile back. went to hook up my hydraulics to the 960 ford. hyd fittings were different. replace them and the cylinders works fine. grease it all up, replace a blown tire and went to hook it up but ran into a problem. drive shaft wont go on the pto. it will start on ut only goe couple inches. don't see any burrs. looks clean, removed the locking pin to make sure it wasn't the problem. I have hooked up several times to this tractor before with other pto drives but I seem to be having a problem that I cant determine on this. I would think the pto would be the same. what do you think.