hey guys i was wondering if someone here would have some advise for me. My dad bought a 1962 Farmall 504 gasser and now that he's got it home he said that when it's cold it shifts fine, but when he gets using it a bit and it warms up he's having problems with it locking in gear, When it cools down again it will shift fine. Was talking to him this morning and he said it is down a little on hyd oil. Would that cause this issue? and should he use Hy-Tran or just hydraulic oil? Sorry for all the questions but neither one of us have much experience with farm tractors and any help is appreciated..