Remember all those jokes about Italian tanks in WWII having four reverse gears and one forward? Well, the Germans have never shown signs of being unduly timid, so the new Mercedes-Benz 7G-Tronic gearbox with its two reverse gears to go with the seven forward does seem a little extreme.
The factory claims that the new transmission – fitted to E-, S-, CL- and SL-Class Mercs from now on – will offer fuel consumption around 5% better, quicker acceleration and slicker shifting than the current five-speed auto boxes. The gearbox will skip gears if necessary on downchanges, which the Germans reckon will save over two seconds on the sprint between 60 and 120 km/hr. But then, they lied about Poland too.
Despite its greater torque-carrying capacity and additional ratios the new transmission is only 41 millimetres longer than the previous version, while the diameter of the torque converter is actually 20 millimetres smaller than before. And despite the seven gears, there is virtually no difference in weight between the two transmissions – the transmission housing is produced from magnesium, and the 7G-TRONIC weighs in at just 81.5 kilograms, excluding the control unit.
Mercedes-Benz has built more than eleven million automatic transmissions since 1959, and should know what they’re doing. Auto boxes are standard in the S-Class and are specified in around 88 per cent of E-Class models. In the C-Class, 65% of cars sold are fitted with automatic transmission, and the trend is rising.
I still haven’t worked out a need for a second reverse gear though. Perhaps there was just a cog left over in the box…