By on May 17, 2019


GMC’s new-for-2019 Sierra 1500 took a less controversial styling route than its Chevy Silverado sibling while retaining the numerous upgrades foisted upon the next-generation pickup twins. For 2020, GMC tweaked the light-duty Sierra’s offerings just a bit, hoping to lure more finicky buyers into the model.

For starters, GM’s 10-speed automatic transmission has a new engine to mate with, hopefully boosting fuel economy ratings that fell for the 2019 model year.

The move to a brasher front end for the next-generation design led to an MPG downgrade for models equipped with the 5.3-liter V8 engine, despite the fact that the new trucks shed weight compared to their predecessors. GMC now says the 10-speed will be available with the 5.3L equipped with Dynamic Fuel Management, GM’s fancy new cylinder deactivation system. The previous transmission pairing was an eight-speed auto.

For 2020, GMC makes the 5.3L/10-speed combo “standard on the Sierra Denali and Sierra AT4 and available on all four-wheel drive Sierras with the SLE trim level and above.” It’s worth noting that the SLE and Elevation trims carry a standard 2.7-liter turbo four-cylinder, mated to the eight-speed auto.

That engine earned praise for its power, but not for its fuel economy.

While the addition of the smooth 10-speed to the smaller V8 engine is a welcome upgrade, higher-end buyers will probably remain tempted by the optional 6.2-liter, a favorite among TTAC staff.


If less displacement and greater torque is what turns your metaphorical crank, the 3.0-liter Duramax inline-six turbo-diesel, which appeared in the Sierra lineup as a late-2019 addition, continues onward. The 277 horsepower, 460 lb-ft mill can be ordered in Denali, AT4, SLT, Elevation and SLE trims. For 2020, however, buyers can pair it with GMC’s pricey, prestigious, and seemingly indestructible CarbonPro bed — another late addition to the lineup. Only the top-flight Denali and runner-up AT4 see this build configuration.

Also new for 2020? The brand’s Adaptive Cruise Control – Camera system becomes available on SLT, AT4 and Denali trim levels, allowing the truck to come to a full stop with the cruise control set. The ProGrade Trailering System, a trick camera setup that turns your trailer invisible for easy rearward viewing, also appears on the 2020 Sierra options list. The system debuted on the redesigned 2020 Sierra HD.

[Images: General Motors]

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15 Comments on “2020 GMC Sierra 1500: More Diesel, More Speeds...”

  • avatar

    More ugly

    • 0 avatar

      Maybe I’m weird, but I actually don’t mind the few Silverados I’ve seen in person.

      • 0 avatar

        Silverado LT TrailBoss in a monochromatic red looked pretty good seeing one in the early morning light a few weeks ago.

        However there was a late teens early 20s female behind the wheel with gigantic hoop earrings.

        Daddy’s truck?

      • 0 avatar

        The one silver lining of these is that all of a sudden the K2XX trucks now look modest and borderline handsome (until a GMT400 pulls up in traffic).

  • avatar

    10 speed everything but the base V6 ya cheap a$$holes.

  • avatar

    More grill!

  • avatar

    What I really want for my next Sierra is a 6.2L with the Double-Cab. It exists according to the configurator, although pretty high up on the trim lines, but I’ve yet to ever see one online.

  • avatar

    So 10 speed means worse MPG? What the hell is the purpose of changing it then? More speeds aren’t bragging rights, 4 and 6 speed transmissions have proven their reliability and cost effectiveness. What does this 10 bring over the 8 if not MPG?

  • avatar

    So 10 speed means worse MPG? What the hell is the purpose of changing it then? More speeds aren’t bragging rights, 4 and 6 speed transmissions have proven their reliability and cost effectiveness. What does this 10 bring over the 8 if not MPG?

    I enjoy the 24-25HWY upwards 30+ on some trips my 17 4×4 5.3L+6 speed Silverado gets. My engine also doesn’t shut off like a 1970s jalopy.

    • 0 avatar

      “What does this 10 bring over the 8 if not MPG?”

      GM’s 8L90 kind of sucks to drive and the 10A is much nicer. Obviously reliability is unknown on it for now. The old 6A is fine too IMO.

      • 0 avatar

        Probably most will be trading up from a 4 or 6-speed auto. What scares me is the rebuilding costs of a 10-speed.

        But vs the 8-speed, the 10-speed has slightly more aggressive lower gears, obviously closer spaced with an extra overdrive (on top) that takes a slightly deeper cut.

        Yeah it has to perform slightly better/faster, with slightly better engine braking and fuel economy, at least in theory.

        Of course this assumes same axle (final drive) ratios.

        You could say trucks used for heavy towing on steep grades can never have enough gears, but it’ll take a 20-speed to impress me. Maybe an overdrive for reverse? Yes I’ve had one (Gear Vendors splitter) back in the ’90s. You ever do 55 MPH in Reverse?

      • 0 avatar

        I never drove the 8 speed, work truck I have is the 2017 6 speed LT trim and I’ve been impressed with MPG to say the least.

        10 speeds seem highly unnecessary based on my results, I would like to try both the 8 and 10 though I couldn’t bring myself to be seen in any of the new trucks as horrible as they look and as cheapened as they look compared to the already cheap out going trucks. If they go any cheaper on the metal in these trucks then bugs will start denting it, From a quick knock the bumpers of these new GMs sounds like aluminum which is a step too far imo. Portions of the body, fine, bumpers not a chance.

    • 0 avatar

      Um, it doesn’t say the 10 speed decreased fuel economy. The new body style with the 8 speed reduced fuel economy compared to the previous generation.

      The 10 speed has been out for a while now, with no major hickups (unlike the 8 speed).

      And yeah, we all miss the 30 MPG V-8 4×4 trucks of yesteryear. Those were the days. I miss them as much as those famous Hemi Dakotas!

  • avatar

    Is the interior rubbish.

  • avatar

    I like the LED lighting.

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