The Audi A4 is a compact executive car produced by the German car manufacturer Audi AG since late 1994. The initial generation A4 succeeded the four previous generations of the Audi 80. And just like its Audi 80 predecessor, the Audi A4 automobile layout consists of a longitudinally orientated engine at the front, with transaxle-type transmissions mounted immediately to the rear of the engine, again, orientated longitudinally. Drive output is transmitted to either the front wheels, or, utilising Audi's 'trademark' quattro permanent four-wheel drive system via a Torsen centre differential.