In recent discussions about power steering systems, the term ATF was used,
unfortunately that's only partially true. There are different types of 'ATF'
around. There are two major types, Dexron from GM and Type F from Ford.
Other companies generally adhere to one of these standards. These fluids are
incompatible, both for foaming and their effect on the sealing rubbers.

My VW manual specifically states that Vanagon power steering systems use ATF
Dexron.

Best Regards

D