MERCEDES has announced a new nine-speed automatic gearbox for the E-Class. The 9G-TRONIC, as it is called, will appear first in the six-cylinder E 350 BlueTEC diesel.
Most current Mercedes automatics are seven-speeders, while BMW, Jaguar and Land Rover make heavy use of ZF’s eight-speed automatics. One other nine-speed automatic – designed by ZF, initially for use in the Range Rover Evoque, was announced earlier this year.
The new gearbox allows a wider range of ratios, with 120km/h (about 75mph) in the very high top gear corresponding to an engine speed of just 1350 rpm, a combination that should make for relaxed cruising and good fuel economy. Mercedes is claiming 5.3 litres of diesel per 100km, equivalent to about 53mpg, while CO2 emissions – 138g/km for the saloon and 144g/km for the estate – benefit too.
Among the other gains from the switch to 9G-TRONIC are quicker shifting and a saving in weight thanks to measures such as the use of aluminium for the torque converter housing.
The new ‘box is suitable for rear-wheel and all-wheel drive cars, and can be used with hybrid and plug-in hybrid drive systems as well. Mercedes says that it will eventually spread to almost all model series and engines in its range.