The automatic gearbox is controlled electronically. The gears are shifted up or down automatically according to preset gearshift programmes.
When you drive at moderate speeds the gearbox will select the most economical shift programme. It will then change up early and delay the downshifts to give better fuel economy.
If you drive at higher speeds with heavy acceleration, if you open the throttle quickly, or if you use the kick-down or the car's maximum speed, the gearbox will automatically select the more "sporty" shift programmes.
Different types of automatic gearbox are installed in different models:
multitronic gearbox
The multitronic gearbox uses a continuously variable transmission (CVT). Torque is transmitted via a multi-plate clutch. Unlike conventional automatics, the gear ratios are not shifted in fixed steps but continuously variable. This gives smoother transmission and makes for better fuel economy.
S tronic gearbox
The S tronic is a dual-clutch gearbox. Torque is transmitted via two independent clutches. They replace the torque converter found on conventional automatic gearboxes and allow for smooth, uninterrupted acceleration of the vehicle.
tiptronic gearbox
In the tiptronic gearbox, torque is transmitted via a torque converter.