My Scag Turf Tiger, with 1300 hours on it, is suffering from a weak drive on the left side. This happens both in forward and reverse so it is not a simple matter of adjusting the control rod, although it does seem to be more of an issue in reverse than forward. The right side has good power, so I have to assume it is an issue with either the left hydraulic pump or left hydraulic drive motor. Before anyone suggests that this might be the dump valve not fully closed, I did check that. I first noticed this 2 or 3 months ago, and it has become worse over time. The amount of weakness seems inconsistent -- sometimes the wheel does not rotate, even on a level surface, other times, and at best, it is just moderately weak. A couple years ago I replaced the seals in the right hydraulic motor because there was a visible leak, but there is no sign of a leak currently. This troubleshooting goes beyond my mechanical expertise and I do not want to guess wrong on what part to replace. I have not found anything that would qualify as a true rebuild kit for the hydraulic pumps and motors, just seal kits, and the costs of the pump and drive motor are too much to guess wrong. If anyone can point me toward rebuild kits, or a source for a rebuilt pump and drive motor, I would be grateful. Thank you for all comments and suggestions.