I have a John Deere 5400, dual remotes with a 520 loader. I bought the tractor basically as a "fire sale" deal as it was. Everything in the hydraulic system works fine with the exception of the 3 point lift arms. When I picked the tractor up, the lift arms were locked in the up position with the drop rate valve, which was closed. I opened the valve and the arms dropped, but they will not lift again. I know there is no problem with the pump because everything else works, and I don't think the problem is in the lift cylinder for the 3 pt. arms, because they were locked in the up position. I removed the drop rate valve, checked it out, and reinstalled it to no effect. I know there is the pressure releif valve, but I don't think there is most likely a problem with it since the loader works fine. Has anyone else had a problem along this line, and if so, can you give me any advice, or at least get me headed in the right direction? Thanks,