This is just a Up-date to my question about Hydraulic pumps failing because of my use of equipment on Hills. Seems this is a common problem for the ZD models with certain Serial #'s. My service dealer called me and told me Kubota would pick up the cost of the parts and they would install a overflow resorvoir to be supplied for extra Hydralic oil so that when your on a hill it doesn't suck dry the pumps. Kind of like how the Coolant resorvoir works. The right side pump was at 50% of left side although they will replace both sides. I'm a happy camper. The mower has 450hrs on it and has been out of warrenty for more than a year.