If you read the spec sheet on that stuff, http://www.q8oils.co.nz/Images/Data/...20Dynobear.pdf
It sounds like it's the greatest thing since sliced bread. They recommend it for use in all areas of machine tools including spindles & ways, which normally use very different lubricants. My spindles get 10 weight & my ways get Vactra, which is similar to chain & bar lube for a chain saw, but a little thicker.
In hydraulic systems, the most important thing is to have a fluid that is compatible with the seals
that are used in the various glands. unless you know what material the seals
are made out of, I think that it is going to be hard to cross that particular fluid to something else. An incompatible fluid will likely either swell, harden or disintegrate the seals.
I would try to contact the manufacturer of the steering
system & see if they can give you some more information.