Hello, I have a 1966 Ford forklift serial # 40506S... I have been able to get most mechanical parts for a 4000 tractor. Recently my power steering went out. can still turn, but dramatically worse. Problem started over nite. steering fluid comes from the gear pump that also runs the rest of the hydraulics which work fine. I have taken apart the rotary pump under the steering wheel. It was clean and in good shape. I checked the relief valve on the pump also free. I then pulled the steering cylinder and made no difference. I checked pressure at the gear pump and have 1100 psi. So far has me stumped. Any ideas or suggestions would be greatly appreciated. Thank you