According to Autoweek, Mercedes-Benz has rather quietly introduced a new nine-speed automatic transmission in Europe. Its first application is in the diesel-powered E350 BlueTec, where it replaces the previously used seven-speed unit in rear-wheel-drive applications.
Known as the 9G-Tronic, the gearbox was designed and is built by Mercedes itself. While acceleration to 60 miles per hour is unchanged despite the two additional ratios, the European Combined fuel mileage rating jumps from 42.8 mpg to 44.4 mpg (both US) thanks to significant increases in the city cycle.
Mercedes has confirmed that the new 9G-Tronic will eventually make its way to the States, but hasn't offered any timetable on its US arrival. When it does, though, it may appear first in gasoline models, as its diesel pairing in Europe isn't a combination offered in the US.