Overseas, Mercedes-Benz has introduced a new nine-speed automatic transmission that it says will help its diesel-powered E350 Bluetec sedan achieve class-leading fuel-efficiency. Replacing the 7G-Tronic seven-speed automatic transmission, the creatively named 9G-Tronic will use a traditional torque converter like any other standard automatic, but it will have two oil pumps to keep all of its gears lubricated.
Mercedes-Benz says the combined fuel economy rating for the 2014 E350 Bluetec is expected to come in around 42.7 mpg in European testing. We don’t expect the car to be quite that efficient in EPA testing, as that’d be a huge jump from the current E350 Bluetec’s 22 mpg city/32 mpg highway/25 mpg combined fuel economy rating. However, the engine is rated at 252 horsepower in the new car versus the 2013 model’s 210, so there could be plenty more reworking to make this engine deliver on the fuel economy front.
Mercedes-Benz claims that with the new 9G-Tronic transmission, the car’s engine will be spinning at just 1,350 rpm at 75 mpg. Coupled with the fact that its drag coefficient is just 0.27–the same as a Chevrolet Volt–and that number seems all the more likely.
The transmission will make its debut in the European-spec diesel-powered Benz, but the automaker says it will be spreading throughout its lineup in rear- and all-wheel-drive models as well as gas, diesel, and hybrid cars and crossovers. At the moment, most Mercedes-Benz models come equipped with a seven-speed automatic. The high-horsepower Mercedes-Benz S65 AMG and SL65 AMG have five-speed automatics because the newer transmissions cannot handle the amount of torque their engines produce.
We’re interested to see how–or even if–Mercedes-Benz will handle the number of transmissions it uses when the nine-speed auto goes on sale in the U.S.