Hey was working on an older John Deere today. It was leaking hydrolic fluid pretty severely from under the steering column. Well I cleaned off the little power steering box (a little box with a bunch of lines running into it, as well as the steering shaft), and after moving the wheel back and forth for a bit found the leak to be coming from where the steering wheel shaft goes into the box. I then removed the box and found a small black rubber gasket that sits under some crush washers. After replacing the gasket and tightening everything back down the leak is gone, yay! Dunno if this will help anyone else, but always willing to share....Ill also be working on a lot of Deeres here shortly.