Combined engine, gearbox, hydraulic oil.

[Bluest]

I don't think I need to worry too much about regressing the Stone Age just yet. I don't think we are in imminent danger of social collapse!

Oil choice here is huge, but just not for UTO for some reason, unless I'm looking in the wrong place of course.

 

[fortec]

That's what is correctly termed an STOU (Super Tractor Oil Universal). Much more common in the UK and Europe in general than in the USA. You will find that most oil companies over there have one in their product range.