7G-Tronic

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7G-TRONIC is Mercedes-Benz' trademark name for its seven-speed automatic transmission. This fifth-generation transmission was introduced in the Fall of 2003 on 8-cylinder models, and was the first seven-speed automatic transmission ever used on a production vehicle.

The 7G-Tronic debuted on five different eight-cylinder models: the E500, S430, S500, CL500, and SL500. Since then, it has been applied to all eight-cylinder Mercedes-Benz models. It is also available on some six-cylinder models including the new 320 CDI engines which uses a VTG turbo charged common rail diesel engine. However, some new Benz models still retain the 5G-TRONIC, notably the V12 engined S-Class and CL-Class cars, as the 7G-TRONIC transmission cannot handle the torque from the V12. As well, while rear-wheel drive E-Class cars have adapted the 7G-Tronic, these with 4MATIC retain the five-speed automatic as of 2008.

The company claims that the 7G-Tronic can save up to 0.6 litres of fuel per 100 kilometers (depending on the car) and has shorter acceleration times and quicker intermediate sprints than the outgoing 5-speed automatic transmission.

The 7G-Tronic has two reverse gear ratios: 3.416 and 2.231. The winter mode, also recently named 'comfort' mode, starts out in 2nd forward and 2nd reverse.

The transmission can skip gears when downshifting, allowing for quicker acceleration. It also has a lockup torque converter on all seven gears, allowing better transmission of torque for improved acceleration. The transmission's case is made of magnesium, a first for the industry, to save weight.

The 7G-Tronic is the fifth-generation transmission for Mercedes-Benz. The automaker has produced over eleven million automatic transmissions since 1959. About 65 percent of Mercedes-Benz C-Class sedans, wagons, and sport coupes are purchased with automatic transmissions (with that figure rising.) However, about 88 percent of Mercedes-Benz E-Class sedans and wagons are purchased with automatic transmissions, and automatic transmissions are standard on the Mercedes-Benz S-Class.

The 7G-Tronic transmission is built at the Mercedes-Benz Stuttgart-Untertuerkheim plant in Germany, the site of Daimler-Benz's original production facility.

AMG Speedshift MCT

A newer version of the 7G-Tronic which is coupled to a mechanical clutch instead of a torque converter, thereby enhancing shift speed and fuel economy. It is available on the 2009 SL 63 AMG.

Gear ratios

1 2 3 4 5 6 7 R-1 R-2
4.377 2.859 1.921 1.368 1.00 .82 .728 3.416 2.231

See also

References