Check the traction boost linkage on the bottom side of the hydraulic pump. Control knob "A" should be locked down into the pump body detent. If it has worked loose (or in some cases fallen out) and the linkage to the snap coupler is not adjusted properly (or missing as in my case) the pump goes into full lift and ignores the hand control. If that doesn't work, your pump's internal control valves may be stuck in full lift. You can try and turn control knob "D" on the front of the pump all the way in. This may unstick the valves. If not, you'll have to pull the pump and disassemble it.