Hi there, I have a 1956 JD model 50. I was headed out to bush hog with it and the PTO shaft is frozen and will not rotate. I helped my dad restore this tractor as a kid and we have not worked it very hard since other than towing a harrow and riding it around. Any insights on how to solve this would be appreciated. I’ve got fields to mow and would like to use it. I thought I would ask before I jumped in and tore it down.