Development of automatic transmissions has accelerated rapidly in recent decades. For years, a four-speed automatic was the standard and few deviated from it, but in the last few years to deal with tougher emissions and economy standards, we have seen the seven-, eight and now nine-speed automatic transmissions. Mercedes-BenzMercedes-BenzGermany, 1924 > present197 models
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will debut its new nine-speed automatic that it calls the 9G-TRONIC on the E350 BlueTECMercedes-Benz E350 BlueTE...United States of America, 2011 > present3 photos
. Orders for the car begin right now and does not change the car's price. It replaces the 7G-TRONIC.

The nine-speed uses a traditional torque converter to transmit power and comes standard on the E350 BlueTEC sedan and estate. Mercedes claims that the E350 BlueTEC will be the most fuel-efficient six-cylinder diesel model in its class because of it. Fuel economy is rated at 5.3l/100km (5.5l/100km in the estate) and emits 138g/km of CO2 (144g/km of CO2 in the estate). That is a reduced of 0.2l/100km and 4g/km of CO2 over the previous seven-speed automatic.

The two extra gears lower engine speeds while cruising, which also means less noise in the cabin. While cruising at 120km/h, the engine is turning at just 1,350rpm.

The E350 BlueTEC is otherwise untouched. It produces the same 248hp from its V6 diesel engine

The new nine-speed is exactly the same size as the seven-speed, so it can be added to any car that previously had it, including cars with start/stop. It is made from aluminum and magnesium with a plastic oil pan to keep weight down.

Sales of the E350 BlueTEC with the nine-speed will begin in September. Prices, which include 19% German VAT, start at €54,710.25 for the sedan and €57,923.25 for the estate.