Not that long ago, many automatic transmissions had just four forward speeds. In an effort to optimize fuel economy, the upgrade was made to 5- and 6- speeds over the last few years. Some luxury car makers offered more speeds, but now automakers are pulling out all the stops for the masses with Chrysler and Hyundai introducing 8-speeds in their 300 and Genesis models. Honda and Hyundai are said to be developing 9-speed units and rumors suggest that Hyundai and Kia are releasing 10-speed gearboxes in 2014.
Why More Speeds?
Simply put, with more forward speeds, the cars can always be in the optimum gear for any situation. As the car accelerates, there is no need for the engine to speed up and then make a huge drop in RPM as the transmission shifts up. With more gears, the transmission can seamlessly advance from gear to gear without the dramatic engine speed changes that can hamper fuel economy. More speeds also offer more gear ratio options at highway speeds.
Is This Really Progress?
If these gearboxes prove to be durable, there is no question that these “plenty-gear” units are huge step forward in terms of fuel economy alone. Eight and nine-speed transmissions are said to offer 15% fuel savings over today’s conventional units. Automakers are investing $Billions into transmission technology, so if your next vehicle delivers considerably improved fuel economy, there’s a good chance that the transmission will play no small role in this.
Globe and Mail: Automatic transmissions gear up for better fuel efficiency