GM High-Tech Performance Blogs
Don't Expect the 8-Speed in Other Models Just Yet8L90 Transmission
February 3 2014 06:36 AM
Gm News, Drivetrain
But rest assured it is coming...
Almost no matter how awesome a new product is that GM releases, we ask "what's next" almost immediately. When Chevrolet unveiled the 2015 Corvette Z06, everyone immediately asked about a ZR1. And of course the official response was that they have no plans to build another Corvette model. Why would they? They still have testing and development to complete on the Z06. Plus that would be terrible form in terms of marketing. Well the next question was, "could we see this amazing 8-speed automatic transmission in something else like the Stingray?" And GM did let on that the answer was "certainly" (according to AutoGuide), but it won't be for the 2015 model year.
The extensive recalibration and integration into the electronic systems makes it time-prohibitive from dropping the 8L90 into the Stingray this year (according to Corvette Chief Engineer Tadge Juechter), which would also likely receive a less expensive and less durable variant of the Z06's beastly slushbox (capable of handling 738 lb-ft of torque). GM truck engineer Jeff Luke also chimed in that an 8-speed will soon join the truck lineup as well, but will obviously need to be converted to a traditional layout (non-transaxle). Homologating the 8-speed across several models not only helps GM recover the R&D costs, but it also allows these vehicles to run a numerically lower final drive (rear end gear), for better highway gas mileage, without sacrificing performance.
Not impressed by all this new fangled technology? Consider this factoid: my 2008 Trailblazer SS gets 14mpg combined highway and city every day (with a 4-speed auto, AWD, and a 6.0L LS2). However, the 2014 Sierra with a 6.2L (L86) and 4WD gets 14/20mpg while making 420hp and 460 lb-ft of torque, despite being considerably heavier and having a larger engine. Now imagine what an 8-speed will do.