In Reply to: 601 oil leakage from hydraulic sump to transmission posted by Richard NY 2N on May 27, 2018 at 16:18:44:
You're not going to like to hear this...
There are two tubes that go through the bottom of the transmission case for the hydraulics on that tractor. They are known to rust through - after 60 years. What is happening is your pressure line has a hole in it and is essentially emptying the hyd reservoir and over filling the transmission and causing it to puke oil out of the shifter.
There is a fix. I haven't done it myself. It requires inserting a new, smaller tube through the old one. I think? it requires a rear split to repair. There is likely some members here who can give you more info than I. If not I have seen numerous threads about it on the YT Ford board.
I mostly just mess with the 3 banger Fords and on those the hyd lines are external or the pump is in the rear.