I know nothing about the Amsoil hydro oil product, but have heard only good things about thier products especially from fellow diesel operators. But one thing I do know is to not substitute the hydro trans fluid filter with an automotive engine oil filter. Auto oil filters most often contain an anti-backflow and pressure relief valves that cannot be used with the hydrostatic transmission system. Get an OEM filter for the tranny, well worth the few extra bucks for the right thing there. Just MHO, but I tend to agree with the others to use the OEM recommeded stuff all the way with the hydros. You don't change the fluid all that often, so it shouldn't be a considered cost prohibitive maintenance task. The Sunstrand hydro in my 682 is 26 years old and has always operated without a hitch, so I can attest to the quality of the fluids Cub Cadet has sold, the same can't be said for Amsoil in the case of my Cub Cadet ownership.
-Fordlords-