Mercedes-Benz 7G-Tronic transmission

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7G-Tronic (coded 722.9) is Mercedes-Benz's trademark name for its seven-speed automatic transmission. This fifth-generation transmission was introduced in the Autumn of 2003 on 8-cylinder models, and was the first seven-speed automatic transmission ever used on a production passenger vehicle.[1]

7G-Tronic
Overview
Manufacturer Daimler AG
Production 2003–
Body and chassis
Class 7-speed longitudinal automatic transmission
Chronology
Predecessor 5G-Tronic
Successor 9G-Tronic

The 7G-Tronic debuted on five different eight-cylinder models: the E500, S430, S500, CL500, and SL500. 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, all V12-powered cars such as the S600 and S65 AMG still retain the 5G-Tronic, which has a torque capacity of 796 lb·ft (1,079 N·m), as the newer 7G-Tronic is limited to 542 lb·ft (735 N·m), not enough to handle the torque from the V12 engine.[2] Also, while rear-wheel drive W211 E-Class cars have adapted the 7G-Tronic, these with 4MATIC retain the five-speed automatic, although the next-generation W212 E-Class released for the 2010 model year adopted 7G-Tronic all across the lineup including 4MATIC.

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.[1]

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. 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.[citation needed]

The 7G-Tronic is the fifth-generation transmission for Mercedes-Benz. 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.

The 7G-Tronic is currently available on the SsangYong Chairman W.

In July 2009, Mercedes-Benz announced they are working on a new nine-speed automatic.[3]

AMG SpeedShift MCT[edit]

Mercedes-AMG developed the 7-speed MCT "Multi Clutch Technology" planetary semi-automatic transmission.

The MCT transmission is essentially the 7G-Tronic automatic transmission without a torque converter. Instead of a torque converter, it uses a compact wet startup clutch to launch the car from a stop, and also supports computer-controlled double declutching. The MCT (Multi-Clutch Technology) acronym refers to a planetary (automatic) transmission’s multiple clutches and bands for each gear.[4]

The MCT is fitted with four drive modes: “C” (Comfort), “S” (Sport), “S+” (Sport plus) and “M” (Manual) and boasts 100 millisecond shifts in "M" and "S+" modes. MCT-equipped cars are also fitted with the new AMG DRIVE UNIT with innovative Race Start function. The AMG DRIVE UNIT is the central control unit for the AMG SPEEDSHIFT MCT 7-speed sports transmission and all driving dynamics functions. The driver can change gears either using the selector lever, or by nudging the steering-wheel shift paddles. The new Race start Function is a launch control system which enables the driver to call on maximum acceleration, while ensuring optimum traction of the driven wheels.

It is available on the 2009 SL 63 AMG and E63 AMG, and will be used for the 2011 S63 AMG and CL63 AMG, and the 2012 CLS63 AMG and C63 AMG.

Specifications[edit]

Gear ratios[edit]

Gear 1 2 3 4 5 6 7 R-1 R-2 Final
7G TRONIC 4.377 2.859 1.921 1.368 1.00 .82 .728 3.416 2.231 2.85
7G TRONIC for Mercedes-Benz S500 2006 4.377 2.958 1.961 1.398 1.00 0.807 0.494 3.154 2.132
AMG-SpeedShift 7G TRONIC (Mercedes-Benz R171 SLK 55 AMG)[5] 4.38 2.86 1.92 1.37 1.00 .82 .73 3.41 ? 3.06

AMG SpeedShift (2004-)[edit]

The performance features found in 5G-Tronic family was first used in 2005 Mercedes-Benz SLK 55 AMG.[6]

In 2007, 7G TRONIC transmission with AMG SPEEDSHIFT was also called '7G TRONIC Sport'.[7]

See also[edit]

References[edit]

External links[edit]