I checked out all the suggestions that you said. I did have a loose fitting and the fluid was getting air in it . I tightened up the fitting and still no better. I jacked up the mower and ran for 1 hr. to get all of the air out of system, when the mower is jacked up the wheel runs fine. When the machine is on the ground I still have no motion out of this wheel. Is this possibly a wheel motor and how can I check wheel motors and pumps to see if they are the problem. Thanks for your help.