Me three.
I am not an expert but to me the SUDT is not being used the same as hydraulic oil. Hydraulic oil is just pumped to the cylinders with minimal wear except for seals. Since the SUDT is doing this plus going through the HST+ transmission it would seem to me there is more of an opportunity for foreign matter from clutch discs and other components in the drivetrain to get in the SUDT. Kubota didn't install three filters just for fun.
I think it is false economy to go with cheaper lubricants on an expensive machine. I run synthetic lubricants in all my vehicles and machines from my Honda lawn trimmer to my 2012 F250 diesel. Synthetics have served me well for more than 30 years.
I am not an expert but to me the SUDT is not being used the same as hydraulic oil. Hydraulic oil is just pumped to the cylinders with minimal wear except for seals. Since the SUDT is doing this plus going through the HST+ transmission it would seem to me there is more of an opportunity for foreign matter from clutch discs and other components in the drivetrain to get in the SUDT. Kubota didn't install three filters just for fun.
I think it is false economy to go with cheaper lubricants on an expensive machine. I run synthetic lubricants in all my vehicles and machines from my Honda lawn trimmer to my 2012 F250 diesel. Synthetics have served me well for more than 30 years.