Audi has made a great many enhancements to the seven-speed S tronic — which has superseded the multitronic — for the A7 Sportback with front-wheel drive. In contrast to the quattro S tronic, the clutches are no longer radially stacked but rather axially positioned one behind the other. They can be separately supplied with oil as needed. Their compact size allows for low moments of inertia at whichever clutch is inactive. Power flows from the output shaft via a spur gear to the pinion shaft first and then to the front-axle differential.
The dual-clutch transmission houses a centrifugal governor in its dual-mass flywheel. Its masses, one attached to each side of the flywheel, move so as to offset the engine’s torsional vibrations. The centrifugal governor significantly reduces these unwanted vibrations — particularly between 1,200 and 1,400 rpm. The engine can consequently operate at very low engine speeds.
Audi’s new seven-speed S tronic has two separate oil supplies. A 4.5-liter circuit of ATF (Automatic Transmission Fluid) services the dual clutch and mechatronics, comprising the control/operation module as well as electronic, electrical and hydraulic components. The wheel set and the differential are lubricated by 3.5 liters of high-viscosity MTF (Manual Transmission Fluid). This division of oil supplies allowed developers to custom-design every component to fulfill its given purpose.