The seven-speed S tronic is composed of two transmission structures. It integrates two multidisk clutches that control different gears. A larger clutch transmits the torque via a solid shaft to the gear wheels for the odd gears 1, 3, 5 and 7. Then, a hollow shaft rotates around the solid shaft and connects the smaller K2 clutch, which controls the gear wheels for the even gears 2, 4 and 6, as well as the reverse gear. The system is well explained in the pictures from the gallery we prepared for you.
Something Audi declared unique for this transmission is two separate oil systems. While the twin clutch, mechatronic module (the "brain of the transmission") and oil pump are supplied by their own oil circuit with seven liters of automatic transmission fluid (ATF) oil, the wheelsets and the central and front-axle differential are lubricated with about 4.5 liters of hypoid gear oil.
As with other double-clutch transmissions, the S Tronic promises not only improved performance because of shorter gearchanges but improved mileage, something very necessary when dealing with AWD.