- The Washington Times - Thursday, October 9, 2003

STUTTGART — A four-speed automatic transmission is quite normal, a five-speed is modern and a six-speed transmission is pretty advanced. But it can always get better.

Mercedes-Benz has just introduced the so called 7G-Tronic, a seven-speed transmission that has been developed especially for six- and eight-cylinder engines with between 300 and 516 foot-pounds. of torque.

It’s the first time that Mercedes has used super-light magnesium for the transmission housing of the 7G-Tronic. It is hardly bigger than that of the five-speed transmission and weighs 16.5 pounds, which is 5.5 pounds less.

Mercedes-Benz did not consider a six-speed transmission because the new 1.6-inch-longer design of the new housing left enough space for seven gears. Questioned if we might expect an eight-speed transmission in the near future, the answer was short and clear: “No, this is it. Eight or more gears do not give extra advantages.”

The advantages of seven gears are reflected not only in a reduced fuel consumption of 0.20 gallon per 100 miles (depending on the engine), but also the emission is lower and acceleration is nearly 0.3 seconds faster in the 0-60 acceleration test. Even better is the acceleration from 35 to 75 mph. For instance for the S 430 it drops from 9.1 to 7.1 seconds and the SL500 it drops from 7.6 to 5.6 seconds.

I had the opportunity to drive with the E 500 and the SL 500 with the 7G-Tronic. It struck me that I did not feel anything of the up- or down-shifting of the transmission. Its electronic control changes gears quickly at generally lower engine speeds.

When multiple downshifting is required, the individual gear stages are no longer shifted one after the other, but can be skipped if required, passing from seventh to fifth, for example and then in third gear.

Using the kick down, the car accelerates briskly but in a very sophisticated manner.

The 7G-Tronic will be available for the eight-cylinder versions, the E 500, S 430, S 500, CL 500 and SL 500.

In the future, the transmission will also be available in combination with the new-generation, six-cylinder engines and for the six- and eight-cylinder diesels.

For instance, it will be delivered with the V-6 in the new SLK that will celebrate is premiere in Geneva in March 2004.

The 7G-Tronic will not be available for the V-12 engines, for which a new five-speed transmission has been developed.

In 2004, Mercedes intends to build 2,800 7G-Tronic transmissions per day.

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