2015 Chevrolet/GMC trucks get new 8-speed automatic
General Motors announced its new 8L90 Hydra-Matic 8-speed automatic transmission will be standard on 2015 Chevrolet Silverado, GMC Sierra and GMC Yukon Denali/Yukon XL Denali models fitted with the 6.2L EcoTec3 V8. GM says this new transmission is roughly the same size and weight as the 6-speed 6L80 it replaces. However, the two extra cogs allow a wider overall ratio spread along with a deeper first gear that will help deliver better off-the-line acceleration. The new transmission also permits the use of numerally taller rear-axle ratios that reduce engine rpm on the highway to further bolster fuel economy.
Additional tech details and official EPA numbers on the 6.2-liter EcoTec3 V8 won't be released until closer to the start of vehicle production in the fourth quarter. GM will say the engine - which can seamlessly transition from eight to four cylinder operation as load factor dictates - will be the most powerful available in any light-duty pickup at 420 horses and 460 lb-ft of torque. It will allow properly equipped versions of these Chevy and GMC vehicles to tow up to 12,000 pounds.
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