I have case 1150b I recently replaced control base gasket and fwd and reverse rings on the rear of the machine.When I went to move the machine I had 280 on pressure gauge than went 0 and would not move. I have checked suction side ,filter , gauge strainer, and the tube above moderator valve . The pump is 6 months old . Took the pump off it looks good and fluid leave is good. The machine will only move a few inch when first started. Could the problem be the pressure relief valve? I am lost looking for help thanks