Use HyTran...it's more expensive but you'll more than likely never have to replace it again. It's better that SAE30 because it traps the moisture that should build up inside and deposits it on the wall of the rearend and not on moving parts. You can get generic HyTran fluid at TSC but if it's a Hydrostatic tranny/rear...Use the IH specific HyTran fluid...Unfortunately, you'll be one arm less after that purchase so invest in a steering wheel spinner...LOL!!!