Lift stuck up

So I was plowing today and when I came to the end of the row and lifted the plows they got stuck in the up position. I did a quick search and saw where it is possible for the control valve to get stuck so I pulled the inspection cover and jiggled the control valve by hand but it didn't accomplish anything. I doubt anyone remembers but last fall I replaced the top cover with a brand new one linkage and all but I didn't replace the control valve or pump. Funny thing is it has been sitting with the lift up for almost 3 hours now and I cant even see where it has leaked down any it almost seems like it's mechanically bound up somehow. Obviously I am going to have to pull the top cover but what should I be looking for?

One thought I had I was dropping off a small hill in the field while I was lifting up the plow I wonder if the piston could have come out of the socket it rides it because the plow was being held up while the hydraulics were going down?

Get a small mirror and a light and look up through the side access hole and see if anything looks out of place. If it stays up overnight, something must be bound up because I can't see the hydraulics staying up that long no matter how good of a condition they are in. Even three hours seems like a long time without dropping at all.

Dan

The piston should not be able to come out unless
something sheared or broke... I wouldn't think.

There should be a plug in the top cover you can
loosen and see if oil comes out. If it does, there
is still pressure holding the lift up, but I've
never seen one hold pressure that long.

It was still up this morning when I left for work so it's pretty much confirmed to be bound up somehow. The hydraulics are in good shape but usually I can hear them begin leaking down as soon as I shut the tractor off its what reminds me to go ahead and let them down.

So much to my surprise it does seem to be a hydraulic problem. I got pa to come over after work and he lifted up on the plows while I pulled the pins out of the lift arms. I then pulled all the bolts out of the top cover including the ones in the transfer plate. Whenever I broke the ones loose in the transfer plate the oring shot out from under there and oil began seeping out as the lift arms began to drop. After reached up and removed the transfer plate my pa absent minded reached over and pushed on the lift arm drenching us both with oil as it shot out!

Once I got the top cover off I checked and all the mechanical stuff was working fine. Once the control levers were removed from the control valve it snapped all the way forward and now it's stuck there very solidly.

Reading in my repair manual it says I have to pull the PTO and all to get the control valve out are there any tricks to replacing the valve without pulling the pump?

If not should I plan on ordering a pump rebuild kit at the same time or just replace the valve itself. I am going to order new PTO bearings, seal and possibly a new PTO shaft itself along with a valve. My tractor serial number tells me I have an early style pump what's different between the two will any parts cross over?

Come on guys I really need some advice from you more experienced fellows on here getting the old girl back together give me a little guidence and I'll run with it.