1967 Propane model; starts great and mast tilts and elevates. But no steering or driving forward or reverse. I removed a small metal line from an electrical solenoid at the top front left side of the valve body and only get oil to shoot out once in a while. My dipstick in the tank says full. I get a clicking when I run power to that solenoid. I hate to remove the valve body then have trouble finding new gaskets..I was going to try more hydraulic oil. What weight does it take? I already googled it...believe me..