I just replaced a blown left hydro pump on my exmark lazer z and can't get that side to work at all now. I put the rear off the ground and worked the levers for over an hour and the wheel is still not moving at all. The side that I replaced is super noisey when ever I move the sticks out of neutral position. I can easily spin it forward or backwards by hand. I have opened and closed the pressure release valves, made sure that the filter is filled to the top, made sure the resevoir is full and cracked and retightend the hoses from the pump to the wheel motor. What have I missed? Is there anything that I am missing? Please help!