Audi’s brand name for the continuously variable transmission introduced on models like the A6 is Multitronic.
Audi launched Multitronic in late 1999, initially in the A6. It was developed with LuK and used a steel link-plate chain running between variable-diameter pulleys, allowing the transmission ratio to change continuously rather than stepping through fixed gears.
Multitronic was designed to combine CVT smoothness with the ability to handle more torque than many earlier belt-driven CVTs. Audi offered it mainly in front-wheel-drive models; it was not paired with the quattro all-wheel-drive system. The system could also simulate fixed ratios for a more familiar, stepped-gear feel.
A common mix-up is Tiptronic, which is Audi’s name for a conventional automatic transmission with selectable fixed gears. Multitronic instead refers specifically to Audi’s CVT family. Audi announced its discontinuation in 2014, replacing it with newer S tronic transmissions.