It sounds like the circuit is open and it is just pumping oil through the valve bank and back to the tank. The valves can be operated manually using a sharp point, screwdriver like. Presuming your unit is similar, you should see two or three cylindrical valves that are horizontal on the top of the unit. If you look at the end of each there is a small hole. With the pump motor running, depressing these inside the hole should move the valves and produce an actuation. I would also check that the dump valve is not jammed in the open position, I question this as the cause as you said you heard the click of the dump valve. The retract, or dump valve operates without the need of the motor. Hope this is of some help.
