Interesting news: Red Line appears to have discontinued their original Synthetic ATF formula, the old Dexron-II spec which was formally approved by Mercedes. It's gone from their website now. For the 722.3/.4/.5 tranny, the acceptable alternative would be D4 or High Temp (but not D6).

On a side note: The 722.6 electronic tranny supposedly requires special fancy MB synthetic fluid, originally 001-989-21-03, spec sheet 236.10, which is Shell 3403 fluid (click here for Shell spec sheet). Guess what: Red Line D4 specs indicate it is a suitable replacement for the Shell 3403 fluid. Amsoil ATF (multi-vehicle) is also suitable for this application. Both Red Line and Amsoil are cheaper than the OE MB fluid, and priced comparable to the Shell/Fuchs aftermarket replacements. Seems like a no-brainer to use Red Line D4 or Amsoil ATF for your 722.6 application.

There are two newer MB OE fluids, which supercede the old... spec sheet 236.12 is for 001-989-45-03 fluid, I believe introduced for the 722.9 seven-speed tranny. The official supplier is Shell/Fuchs/Mobil 3353... it is a low-viscosity fluid similar to Dexron-VI, Again - surprise, surprise - Red Line D6 is approved for this application. There is no current Amsoil fluid that meets this spec.

The latest MB auto tranny fluid spec is 236.14, MB # 001-989-68-03. This is supposed to supercede/replace both 236.10 and 236.12. The OE fluids are Fuchs/Titan 4134, or Mobil/Shell 134. I haven't found any major aftermarket synthetic fluid mfr (Amsoil, Red Line, etc) that has a fluid for this 236.14 application, although I don't really care as I don't own any MB's new enough to need this.

MB spec sheets are here:
http://bevo.mercedes-benz.com/bevolisten/bevo-sheets-sort1.html


Side note: None of the Mobil-1 datasheets or product specs give even the faintest hint that Mobil-1 ATF would be acceptable in any 722.6 Mercedes application, only for older MB trannies requiring Dexron II/III (722.5/.4/.3/.2/.1). However, based on the Red Line & Amsoil compatibility, it is likely that the new Mobil-1 Multi-Vehicle ATF would be appropriate for 722.6 / 236.10 applications only (NOT 236.12 or 236.14). Use at your own risk, YMMV, etc, yadda x3...