Originally Posted by Peter Guenther
The US version, in my case the E320 wagon uses the hydraulic leveling fluid and steerig fluid from the same pump and reservoir. I dont see them changing back and forth from ATF to Hydro Oil, The oil is MB specific.
Actually that is the case across the globe if you have self-leveling suspension. Otherwise it is just the conventional reservoir on the PS pump.
Trevora, to my knowlege MB contracts with some folks to supply these products, in others manufacturers (such as Mobil1) comply with Benz requirements to make oil to meet their specs. Some are just MB specific, MB branded, buy at the dealer, such as ATF and PS fluids. Coolant you can use MB or Zerex G-05.
In each case of an MB-specified product it is designed for the application and uses proprietary additives/base packs.
You've bought a highly-designed-and-engineered vehicle, as I noted previously don't carry too much of the generic mindset forward. Generic lubes are cheaper but may lead to serious damage to expensive components, penny-wise and pound-foolish, as they say on your side of the pond.
Take care and enjoy the ride,