I have a 2002 Husqvarna ZTHKH4818A with about 500 hours. The right drive wheel grabs when decelerating, it just won't decelerate smoothly. Its like the wheel reaches a certain speed and instead of smoothly continuing to decelerate, it just stops suddenly. This causes little tears in the turf when it happens and is a major pain in the butt. I have adjusted the linkages to the hydros to try to find a setting where it won't do that, with no success. What could the problem be? Hydro unit? Wheel motor? Much appreciated if anyone knows how to diagnose this problem or can point me in the right direction.