I run mine with R40, both the engine and gearbox.
The old stuff could gel to an extent and certainly would if it came into contact with mineral oil, but the more modern oil seems fine generally if used neat.
Its main attribute is its very clingy nature which protects far better than the newfangled stuff.
I don’t think I like the idea of mixing it with other oils however, I would go for one or the other —
Mike.
