Six, seven, eight-the great gear debate

Transmission are gaining gear ratios as OEMs search for more fuel efficiency and refinement.

Automakers are realizing what long-haul truckers and Tour de France cyclists have known for years-more gears can be a good thing.

When the trend toward six-speed automatic transmissions in the early 2000s appeared to validate the configuration over four- and five-speed designs, Mercedes-Benz trumped it with the seven-speed W7A700 developed in-house. Getrag and ZF kept pace with their own seven-speed units before Toyota, with its supplier Aisin AW, shot back last year with the world's first eight-speed automatic for rear-drive passenger cars.