4 wheel Electronic Traction System 4ETS Working with the vehicle's full-time four-wheel drive, 4-ETS uses individual wheel-speed sensors to detect the onset of wheel slip. Then it individually brakes the slipping wheels as needed, providing the effect of locking the front, center and/or rear differentials. The 4-ETS system continually balances the torque split to direct power to the wheel or wheels with grip. 4 Wheel Drive and Automatic 4MATIC 4MATIC is the name of a complex electronically controlled all wheel drive system developed and used by Mercedes-Benz on some of its models. All Mercedes cars featuring this system also have an automatic transmission in standard equipment and that's where its name is derived from (4-wheel drive and automatic transmission). Originally developed together by Mercedes and Steyr-Daimler-Puch engineers, the system is now at its third generation but it's still based on a rear wheel drive c...