2009 Mercedes-Benz CL550 gets standard AWD

Mercedes-Benz recently announced that when the 2009 range of its CL coupes goes on sale later on this summer, the entry-level CL550 will get the company's 4MATIC all-wheel drive system as standard equipment. The newest generation of the system adds a negligible 154lbs to the CL550's already substantial 4,485lb curb weight and should help the big coupe make more efficient use of its 381 horsepower and 391 lb-ft of torque.

Other CL models, such as the CL63 AMG, CL600 and CL65 AMG continue with rear-wheel drive only. Thus far, Mercedes will only offer the CL550 4MATIC in the Canadian market, and it's not known when or if the automaker will bring it to the U.S.

The same all-wheel drive set-up made its debut in the 2007 S-Class flagship sedan, and no longer requires unique front suspension parts and wider transmission tunnel. The system's left front wheel drive axle travels through the engine oil pan, and only two gears power the front driveshaft versus the old system's three.

The all-wheel drive system includes an electronics traction control system that, according to Mercedes, will keep the car moving even if only one wheel has traction. Mechanically, a multi-plate clutch in the center differential acts like a limited-slip differential, while a planetary gearset allows for slightly rear-biased (45/55 percent) torque distribution under normal driving conditions.