If you change your filter on hydrostatic tranny ! Make sure you change it with a Cub Cadet Filter ! Or it will not work Cub Cadet has a special valve in it for hydrostatic.
Many manufactures use a filter with a pressure relief valve. It depends on the manufacturer of the hydrostatic transmission. On today's units Cub Cadet can be using trannys made by HydroGear, Peerless, Splicer/Dana, depending on the model. A little investigation will help you find others filter which will work on your unit, at a cheaper price.