I have been using Mobil 1 Delvac synthetic ATF, as that's what was in it when I bought it. I have not been able to find it lately so not sure what I will do when the pail I have is gone.
I usually run a high-quality 10W hydraulic oil in my 262C. You don’t necessarily have to buy the Cat branded stuff, but just make sure whatever you get meets their specifications for anti-wear and zinc content. It's not worth saving a few bucks on cheap oil and risking the pumps.
