General Motors will make Hydra-Matic 8L90 – a new eight-speed automatic transmission – as standard on some 2015 Chevrolet Silverado, GMC Sierra and GMC Yukon Denali/Yukon XL Denali models powered by a 6.2-liter EcoTec3 V-8 engine.
The new gearbox replaces the Hydra-Matic 6L80 six-speed automatic transmission in the trucks. Both gearboxes are produced at GM’s transmission plant in Toledo, Ohio. According to GM, of the new transmission will commence in the fourth quarter of this year, which means it would be a late introduction on 2015 models.
GM will announce more technical details as well as EPA-estimated fuel economy ratings closer to the date of launch. GM remarked that the Hydra-Matic 8L90 will be around the same size and weight as the Hydra-Matic 6L80.
The new transmission, however, provides a higher first gear ratio for towing or hauling heavier loads. Hydra-Matic 8L90 also provides lower rear-axle ratios for reduced engine revolution speed on the highway.
The 6.2-liter EcoTec3 V-8 engine the powers some of GM’s trucks provides up to 420 hp of output and 460 pounds-feet of torque. The engine features an SAE trailer rating of 12,000 pounds. GM is the sole developer of the 8L90.