The transmission, labeled a 9G-TRONIC, is selectable on the configurator of the automaker’s German website and so far is only available with E350 BlueTEC trim, where it replaces a previous seven-speed 7G-TRONIC.
Land Rover was the first to announce a nine-speed automatic for one of its cars, a ZF unit designed for transverse applications. The Mercedes transmission is designed for longitudinal applications and has been developed in-house.
The extra gears are said to yield significant improvements in fuel economy and CO2 emissions. Advantages over dual-clutch units include lighter weight, better reliability, less complexity and cheaper manufacturing and repair costs.
In the E350 BlueTEC diesel sedan, which rates at 248 horsepower, the nine-speed automatic helps the car achieve 0-62 mph acceleration in just 6.6 seconds and fuel economy of 36.75 mpg in the city cycle, up from 34 mpg with the previous seven-speeder. The highway figure remains unchanged at 50 mpg. Note, European figures are listed.
The 9G-TRONIC will eventually feature on other Mercedes models, though its availability will be announced at a later date.
Numerous other automakers are looking to additional gear ratios to eke out further savings in fuel consumption. The aforementioned ZF ‘box will soon be added to some Chrysler products and Ford and General Motors have announced plans to develop new nine- and ten-speed automatic transmissions together.