I have a Exmark Lazer Z HP and the right side hydraulics are getting weak. When going strait, I have to push the right control level further that the left to equal out both wheel speeds. I notice that when I use more of the right side, the engine drop some rpms. I know these hydro parts are pretty expensive, but I dont want to be stuck in the middle of a yard somewhere where that side goes. Does this sound like the drive motor is going bad, or is it the pump? Any suggestions, comments, or advise would be greatly appreciated.