GM Expands New Transmission Use for 2018
CARS.COM — GM isn’t the first mainstream automaker to offer a nine-speed automatic transmission, but it will supply a significant number of them by the end of next year. The Detroit automaker, whose U.S. brands are Buick, Cadillac, Chevrolet and GMC, announced plans to offer the nine-speed automatic as an option on 10 models by the end of 2017.
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Some of those cars will get the transmission starting with the 2017 model year while others will get it for the 2018 model year, GM powertrain spokesman Tom Read told Cars.com. The rollout starts with the 2017 Chevrolet Malibu and Cruze Diesel, plus the 2018 Equinox SUV. Expect the gearbox to pair with front-wheel-drive cars or those that have front-based all-wheel drive, like the Equinox. Read confirmed the transmission works with front-drive engine layouts.
The Malibu’s nine-speed automatic pairs with the sedan’s optional turbocharged 2.0-liter four-cylinder, replacing an eight-speed unit from the 2016 model year. But the resulting 22/33 mpg city/highway in EPA-estimated ratings is just 1 mpg better than the 2016 Malibu’s highway rating with the eight-speed auto. The EPA’s combined rating, 26 mpg, is unchanged.
That raises a familiar question: Past a certain threshold, do more gears have diminishing returns?
“Yes, I think that’s true,” Read said.
But the number of gears isn’t the only factor in a transmission that affects its contributions to fuel efficiency. GM’s current six-speed automatic, which the nine-speed will replace in some vehicles, is “an extremely efficient transmission” in its own right, Read added.
GM developed the nine-speed automatic in conjunction with Ford — among the first fruits of a collaboration more than three years in the making. EPA estimates for the 2017 Cruze Diesel and 2018 Equinox are still pending.
