Farmall 460 hydraulics

Alright here it goes: After an hr or so of using my 460 the 2pt hitch begins to drop and raise continueously causing a noticable strain on the engine as if I was raising a heavy load. Eventually this stops and is replaced with a contiunuous straining noise on the engine. Also the deck where your feet sit, above the transmisson seems to get pretty hot. Also if there is an impliment on the machine such as a wheel harrow and I try to raise the impliment it may not raise up at all (again only when the machines been running for a while when its cold it raises any machine just fine). So far I have two things I have considered. 1 a hung open valve that is bypassing and causing the pump to work coninuously cause the fluid to become overheated and very thin causing which eventually causes a loss of pressure(but where would this hung valve be and how can I check it?). or 2 maybe the pump is just bad. Is there anyone that can point me in a direction to diagnose which of these is the problem because I dont want to go buy a new pump for 400$ if it turns out to be a hung valve or some other minor thing in the system. Anyway sorry for the long posting just want to be specific, if anyone has ideas please feel free to share. Thanks!

id try a filter first sounds like the oil is getting heated up and starving the pump

Yeah that was my first thought too. I forgot to mention that I changed the fluid and have new hytran fluid in it and a new filter. I pulled the pump out too to inspect it but I rally didnt know what I was looking for and didnt want to screw it up so I just put it back in. At least if it ends up being the pump it is pretty easy to replace..... Any other ideas?

Well, for starters, if your hitch is dropping and correcting itself that means it is leaking. You have a check valve under seat to hold cyl up so either that is leaking or the cyl is. With engine shut off and a load on hitch , remove hose that is not holding load up, if hitch is going down oil will flow out of hose if cyl is problem ,if no oil is coming out of hose and hitch is going down check valve is leaking. After you correct hitch problem then you can see if you still have lifting problems and heating.

Matt If the hydraulic is getting hot as you say then the unload valve is staying loaded or high pressure. It could have bad oring bad seat or dirt. It is behind the plate with the 4 3/8 cap screws to hold the 2-1/2 x 3" plate. That plate as a big spring behind it, the pressure relief spring. So remove 2 of the screws opposite each other and put 2 longer screws in so the plate does not fly off.

I took apart both valves. The one under the seat and the one under the dash. Niether of them had rust or any signs of wear. The piston also does not seem to be leaking or bypassing, which was made clear when I reconnected it to the check valve under the seat and relized it was on backwards and would not go up or down and was straining the pump, which I would assume shows that the check valve in the piston is working.... I just find it hard to believe that a bad pump would heat up the oil while working so well when cold but not work at all when hot. I have not run the tractor long enough yet to see if the problem is still occuring after disassembling those parts however I cant imagine it will be any different then before since I didnt really do anything to it. Anyway thanks for the help to all of those who replied. Any more ideas are welcome. Thanks! Matt