Wayne, ATF does stand for Automatic Transmission Fluid. Believe it or not MB does not list any synthetic tranny fluid as an approved fluid for thier transmissions. I have a copy of MB's "Factory Approved Service Products" and it has a long list of approved tranny fluids. To my surprise, Mobil is not one of them. The approved ATF fluids are; Castrol Dextron III/Mercon, Castrol Transmax, Chevron ATF Dextron III, Citgo Multi-purpose ATF, Exxon Superflo ATF Dextron III, Havoline ATF Mercon/Dextron III, Texaco ATF Mercon/Dextron III, Pennzoil ATF, Quaker State Dextron III/Mercon, Sunoco ATF Dextron III/Mercon, Unocal Multi-Purpose ATF, and finally Valvoline ATF Type D. This list is as of Nov. 2001. As you can see there is a wide variety of brands to choice from. FYI "Dextron" is a standard created by GM and "Mercon" is a Ford standard. Most cars on the raod require Dextron grade tranny fluid. As you can see from the list above, none of them are synthetic.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member