Mercedes-Benz is launching an all-wheel-drive version of its new-generation S-Class sedan. With the addition of the S550 4MATIC, all-wheel drive is now available on all three sedan lines (C-, E-, and S-Class), and with its four sport utility families (ML-, R-, G-, and GL-Class), the company now offers 18 different 4MATIC models in the U.S. market.
The successor to a long line of premium luxury vehicles, the new S-Class sedan was launched in early 2006 with the S550 model, powered by an all-new 5.5-liter V8 engine delivering 382 horsepower and 391 lb.-ft. of torque, also the first of a new V8 engine family featuring four-valve-per-cylinder technology and variable valve timing. The new S550 4MATIC features a totally redesigned all-wheel-drive system that’s integrated into the seven-speed automatic transmission.
The new-generation 4MATIC featured in the S550 sedan is redesigned and inte-grated into the seven-speed automatic transmission. The new system fits right into the rear-drive body and utilizes the existing front suspension – gone are the special suspension parts and wider transmission tunnel that were necessary on earlier 4MATIC systems.
Fuel efficiency has been improved over earlier 4MATIC systems, due to a number of innovative measures that minimize the energy needed to turn the extra all-wheel-drive shafts and gears.
In particular, only two gears now power the front driveshaft (instead of the previous three), and the direction of rotation is cleverly corrected in the front final drive without additional gears. Recessing the universal joint for the front driveshaft into the transmission output gear also saved space, helping to better fit the entire drive system into the standard body shell.
The new S550 4MATIC also comes with a multi-plate clutch tucked into the center differential that provides the extra traction benefits of a limited-slip diff while complementing the four-wheel traction-control system. Sometimes called a “breakaway” clutch, the multi-plate unit helps provide power equally to the front and rear wheels when driving straight ahead, but still allows the front wheels to rotate faster in turns. In a sense, the clutch is a proactive traction aid, while four-wheel traction control reacts after wheel slippage is sensed. Developed entirely in-house by Mercedes-Benz engineers, the new S-Class 4MATIC drive layout is expected to find its way into a full range of other models, including diesel-powered vehicles.
The full-time all-wheel-drive system used in Mercedes-Benz 4MATIC cars and all SUVs features a center differential that can vary front-to-rear torque distribution for great on-road handling, not to mention stellar traction in a wide range of conditions. In addition, the system includes innovative four-wheel electronic traction control that keeps the vehicle going even if only one wheel has traction.