The six-speed manual transmission: Comfortable manual gearshifts
The new six-speed manual transmission was developed in parallel with 7G-DCT. It is extremely compact and shares a number of common parts.
The three-shaft transmission is also very compact (length 345 mm) and light (dry weight 46 kg) and incorporates a number of special features for particularly pleasant gearshifting. An integrated magnet on the gearshift shaft is detected by a Hall sensor. The idle position is identified in this way, making the start/stop function possible. The signal for reverse gear activates the reversing lights.
The large spread of 6.7 allows a reduction in engine speed while at the same time ensuring that sufficient tractive power is available when moving off with a fully laden A-Class and trailer up to a gross weight of 3.4 tonnes. The clutch is operated hydraulically and the gears are actuated via cables.
The overhead camshaft with third and fourth gears and the reverse gear do not run in the oil bath. This reduces drag torque, thus facilitating gear shifting at low temperatures in particular. The three-cone synchronisation of the first two gears serves the same purpose, while the following gears are provided with two-cone synchronisation. The weight-optimised cast aluminium shift forks are installed on anti-friction bearings on the shift rods, in order to reduce the shift forces.