2015 Chevrolet & GMC Models to Get 8-Speed Automatic Transmission

GMC Sierra pickup truck 1 photo
Photo: GMC
At this year's Detroit Auto Show, Chevrolet debuted the 2015 Chevrolet Corvette Z06. A new eight-speed automatic transmission has been announced as an optional extra that offers full-throttle upshifts quicker than those of the PDK dual-clutch job on the Porsche 911. Now guess what – that same Hydra-Matic 8L90 unit will be offered as standard on a handful of GM-built pickup trucks and SUV models.
According to the manufacturer, 2015 model year vehicles propelled by the 6.2-liter EcoTec3 V8 powerhouse will be mated to the eight-speed auto. Packing 420 horses, 460 lb-ft of torque and able to operate on only four cylinders to improve fuel economy, the naturally aspirated mill is the most powerful engine offered on a light-duty pickup truck, offering a maximum trailer rating of 12,000 lbs.

Developed in-house by General Motors, the Hydra-Matic 8L90 eight-speed automatic will replace the Hydra-Matic 6L80 six-speed fitted to outgoing models of the Chevrolet Silverado, GMC Sierra, GMC Yukon Denali and Yukon XL Denali powered by the 6.2-liter EcoTec3 V8. Compared to the older transmission, the 8L90 benefits from a wide 7.0 overall gear ratio, which translates to a higher 1st gear ratio to help drivers start off more confidently with a heavy load or when trailering. Moreover, the 8L90 eight-speed enables numerically lower rear axle ratios, which reduce engine rpm when cruising on the highway.

Unfortunately, there's no word if the all-new transmission will eventually be fitted to the 2015 Cadillac Escalade as well, but that's likely to happen considering what the luxury SUV packs under the bonnet. General Motors informs that additional technical details and EPA estimated fuel economy will be announced closer to the start of production in the fourth quarter of 2014.
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About the author: Mircea Panait
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After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well.
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