Builder....I'm using Rotella T Synthetic. It's the Rotella product that comes in the blue bottle. It's about twice as much as the regular Rotella oil. I'd been through hours of discussion on here before I made my decision and frankly I think my post drove off one of the frequent member (GSXR), due to some heated discussion with other members. Anyway, the Rotella T Synthetic is a good synthetic oil, maybe not the best, but I change it every 50 anyway.
The transmission is full of Kubota's synthetic hydro oil "Super UDT". At least that's what I've been told. I don't get all into oil analysis and the nitty gritty of oil specs. I've just trusted those who do (on TBN) to recommend a good oil that's reasonably priced. It's better than what I used to use.
So in a nutshell.....The engine is running Rotella T Synthetic and the Transmission/Hydraulic system is running SUDT. Hope that helps.