When GM released the new Chevrolet Silverado and GMC Sierra pickup trucks in 2013 and the latest GMC Yukon SUV earlier this year, they were offered with a 6-speed auto transmission. Now, GM is stepping up a gear, or rather two, as starting from this fall, the 2015MY Chevy Silverado, GMC Sierra and GMC Yukon Denali/Yukon XL Denali models with the 420hp 6.2-liter EcoTec3 V8 will have a standard 8-speed automatic.
According to the Detroit automaker, the GM-developed Hydra-Matic 8L90 eight-speed has approximately the same dimensions and weight as the Hydra-Matic 6L80 6-speed automatic, but its 7.0 overall gear ratio is spread out more and offers a shorter first gear to help when starting off with heavy load or when trailering.
Further technical details and more importantly, EPA estimated fuel economy figures for all three models fitted with the 8-speed unit, will be released closer to their launch date.
GM didn’t mention the new Cadillac Escalade, but we see no reason why it won’t get the same 8-speed auto as its Yukon sibling down the line. The Chevrolet Tahoe, on the other hand, is not offered with the more powerful 420hp 6.2-liter EcoTec3 V8 (it’s available exclusively with a 355hp 5.3-liter V8), so it will likely continue with the 6-speed unit.
By John Halas
PHOTO GALLERY
