i have an 863. i just overhauled the hydostatic pump reinstaled it in the machine.everything worked at firts now it will not move. the right wheel will move very slow when the machine is up on jack stands.the left wheel does not move at all.one other thing i noticed is that without the machine running you can turn the right side wheels by hand and the left side will not budge unles you crack open the hoses on the drive motor.any help would be great.