In a bid to keep its technological and fuel-economy edge, it appears that General Motors is on the cusp of offering an eight-speed automatic on some models of its fullsize trucks and SUVs. According to information obtained by GM enthusiast forum GM Inside News, models equipped with the top-of-the-line 6.2L EcoTec3 V-8, such as the Cadillac Escalade, GMC Yukon and Sierra Denali, and Chevrolet Silverado High Country, will reportedly receive GM’s in-house-developed 8L90 eight-speed automatic transmission that recently debuted on the 2015 Chevrolet Corvette. The transmission has a maximum torque capacity of 738 lb-ft of torque, more than enough to handle the 6.2L’s 460 lb-ft.
If history is any indication of future plans on the eight-speed, it’s likely it will roll out first in the low-volume 6.2L models and may spread across the rest of the fullsize truck and SUV lineup for the 2016 model year as production capacity ramps up. The 6.2L engine currently gets between 14-15 mpg city and 20-21 mpg highway with the 6L90 six-speed transmission. Expect a bump of about 1 mpg in both city and highway figures with the eight-speed.
Still unknown is where the jointly developed Ford/GM automatic transmission falls in this scenario. The two companies announced a collaboration in April 2013 on developing next-generation transverse and longitudinal automatic transmissions with up to 10 speeds. No rollout timeline was announced on the new transmissions.
Source: GM Inside News