The new Mercedes-Benz SL 63 AMG is equipped with 7 speeds, 4 drive modes, a double-declutching and Race Start function. MCT stands for Multi‑Clutch Technology and only employs clutch elements to perform gearshifts. A new two-stage torsion damper effectively eliminates vibrations. The AMG MCT 7-speed sports transmission has been developed jointly by Mercedes-AMG GmbH and Daimler AG, although it will be used exclusively in AMG high-performance vehicles. It is produced at the Mercedes-Benz Esslingen-Hedelfingen production facility, Europe’s largest manufacturer of planetary gear sets.
At the heart of the new AMG SPEEDSHIFT MCT 7-speed sports transmission lies the wet start-up clutch, which runs in an oil bath and replaces the previous torque converter. Thanks to its low rotational inertia, the transmission responds instantaneously and dynamically with no slip. Accelerator pedal movements trigger an instant traction response. Fitted with four drive modes: “C” (Comfort), “S” (Sport), “S+” (Sport plus) and “M” (Manual), the transmission provides gearshifting with no loss of tractive force and supports customised control strategies for maximum driving pleasure. In “C” mode the gearshifts are comfortable, coupled with a “soft” accelerator response set-up for outstandingly smooth power transfer. In “S” mode the engine and transmission interact with more "bite": the engine speed is allowed to reach a higher level in each gear; the downshifts also feel more spontaneous. The gearshifts are around 20 percent faster than in “C” mode. Switching to “S+” mode cuts another 20 percent off shift times, while “M” is the sportiest mode: here the AMG 6.3-litre V8 engine has even more bite, added to which the transmission shifts gear another 10 percent faster – a reduction of 50 percent compared with “C” mode. In “M” mode the gearshifts take just 100 milliseconds.
Ultra-fast, spontaneous multiple downshifts are another forte of the new MCT sports transmission. For instance, kickdown lets you move straight from seventh down to fourth gear or from fifth to second. In the “S” (Sport), “S+” (Sport plus) and “M” (Manual) modes the automatic double-declutching function is active. Every manual or automatic downshift is accompanied by precisely metered double-declutching – from “S” through “S+” to “M” incrementally. And this not only adds to the driver's emotional experience: the virtually load-free downshift minimises load-change reactions, which pays dividends particularly when braking into a bend on the racetrack.
