I have a lift here busting my knuckles. Any help would be appreciated. This Combilift will crab walk left and right with no issues but when you travel Forward or Reverse the front wheels will go straight but the steer wheel won't move and the steer system starts straining. You're unable to move the steering wheel and the unit won't move. The engine speeds up to compensate for the strained steering system. I've replaced the 4 port valve and the 6 port valve after the steer orbital. I've checked all the relays. When you change the joystick to crab walk left and right the unit works perfect. I found a broke proximity switch on the left front wheel. Would this cause this issue? Does someone have a theory of operation for the Combi trucks since there are very few in my area? Thanks Mike