did a motor swap in a toro time cutter. After putting the pto on I noticed it was not going on all the way. Went to take it off and it's stuck. The weird part is I can get it to go up and down on the crank about a half inch. But won't come off or go all the way on. About a half inch short of going all the way on. I've taken off many pto and have had some trouble before. But not like this. Any suggestions on this one??