just bought a used hustler super z. Had 50 hours and had recently been serviced. I mowed with it last week and noticed that on hills and turn arounds @ slow speeds the left wheel felt like it was grabbing. Go, just with hesitation. I took it to my dealer and they said the hydro wheel mower is shot and I need to be replace. What would cause a hydro with 50 hours to tear up? Should I just go on and replace it or drive it until it totally goes out.?