thinking out loud here...With engine off there is no slack in the steering, the alignment is ok as there is no sign of uneven wear in 3 years. I took the rig for a drive with the pump belt off and the rig drives great except for the muscle required. At highway speed it is far easier to control.

what controls the amount of force that the system apllies? at parking lot speeds isn't the amount of applied force going to be greater than that which is applied at highway speeds?