I have a Walker 1999 with about 1,700 hrs. I noticed that it still seems to go pretty fast in forward, but it struggles when backing up steep hills. My newer machine will go twice as fast up the hill. I need some way to determine if the problem is the hydro, the gear drive or both. I had a failure of a gear drive a few years back and waited too long and the hyrdo burned up also. If the gear drive is a problem, I want to make sure the gear drive is in good shape before I do anything to the hydro. Thanks.