Last year, Lexus became the first automaker to introduce a production eight-speed automatic transmission in the latest LS460. Recently, German transmission manufacturer ZF announced a new eight-speed of its own which is claimed to provide a 14-percent boost in fuel efficiency compared to a five-speed. It looks like Audi and BMW will likely be the first to directly challenge Lexus when they start using the ZF. Audi may be first out of the gate in 2009, with eight-speed installations in the A8, Q7 and the expected A7 coupe. BMW will probably follow a year later with the X6 and the next-generation 7 series getting the extra gears. Mercedes-Benz already has a seven-speed that it builds on its own. Mercedes' powertrain chief admits that an extra gear could be added to the unit but that the incremental improvement would be limited. As more gears are added, the weight and complexity of the system increases and the improvements become smaller and smaller. Seven and eight-speed transmissions will likely remain the maximum for the foreseeable future and six-speeds will probably take the bulk of volume in mainstream segments.
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