In 1989 Porsche introduced the 964 generation of the 911 as a replacement for the long-standing g-series which was produced from 1974 through 1989. The 964 was considered 85% new compared to the old 3.2 Litre 911’s. The first 964’s that were introduced were offered only as c4s which were “all wheel drive”. The first c2s with rear wheel drive were not introduced until 1990. These cars were all offered with the venerable g50 five-speed transmission and a new-to-the-911 “Porsche tiptronic” a load switchable, four-speed, sport transmission. This gearbox was produced for Porsche by zf.