Chevy & GMC Make Quick Transmission Change
22. July 2014
This didn’t take long.
The 2014 Chevy Silverado, GMC Sierra and GMC Yukon Denali/Yukon XL Denali models with a 6.2-liter EcoTec3 V8 were essentially all-new.
These trucks came equipped with a Hydra-Matic 6L80 six-speed transmission.
Those who are going to be getting 2015 versions of those models are going to find that the standard transmission is a Hydra-Matic 8L90.
Yes, the “8” in that alphanumeric signifies that this is an eight-speed transmission.
The new transmission has a 7.0 overall gear ratio spread that’s wider than the six-speed. This means that there is a numerically higher first gear ratio that benefits starting out, especially when there is something heavy on the hitch. In addition, it enables numerically lower rear axle ratios, which reduces engine rpm on the highway, which is beneficial vis-à-vis fuel efficiency (GM will provide EPA fuel economy numbers around the start of production, which is the fourth quarter of 2014).
Once, not all that long ago, something like this wouldn’t have happened until a few years into the production run.
But nowadays, the game is being run that much faster.