Neither Mobil or Mobil 1 ATFs are on the "Approved Service Products List". As strange as that sounds, it is true. There are 12 brands of ATF that are on the list and they are not synthetics. The newer transmissions call for MB synthetic ATF, but for your '92 W124 car, it would call for one of the 12 regular Dextron III ATFs. I am not saying to not use Mobil 1, I am just saying what is on the "list".

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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