Have you ever put a hydraulic pump on your bucket truck Mathew? On our Versalift I have put a new pump and fork in the PTO and a new check valve on the outlet of the pump as the old one was blown. And it simply will not pick up and get going again. I think its starving for oil. This particular hydraulic tank has the oil feeding from the top left hand side, 90's down into a sideways filter to the hose, through the floor out to the pump.