I just picked up a Grasshopper 721D from a city surplus auction ($3100...did I pay too much?). Overall, it looks ok, sounds strong, and the hydros seem strong. It has 1057 hours on it. My question is what kind of recs does anyone have as far as type/weight of oil in the hydros and engine? I want to change all fluids and filters so that I know the status of everything. Thanks for any input..