The Mercedes 722.9 transmission has been around since the later part of 2004, but there still isn't a lot written about it.
This 5th generation transmission is the first 7-speed automatic produced by Mercedes Benz. The Mercedes designation for this transmission is New Automatic Gearbox 2 (NAG2) or 7G-Tronic. Along with seven forward speeds this unit also has two reverse gears ratios (similar to the 722.6) depending on whether it's in Sport or Comform mode.