Audi S4
Audi's quattro four-wheel-drive system was standard on the C4 S4/S6; a first-generation Torsen-based system which used the "T-1" automatically biasing centre differential (ATB) was used on vehicles equipped with manual transmissions, while a transfer box based system was used on vehicles equipped with an automatic transmission.
Audi A6
Also new was the multitronic continuously variable transmission, available in most front-wheel drive models. All models, except the 2.0-litre petrol and 1.9-litre TDI, were available with Audi's trademark four-wheel-drive system, quattro. A four-wheel-drive version of the Avant, with raised ground clearance and slightly altered styling was sold as the Audi allroad quattro, Audi's first crossover SUV.