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2024 GMC Sierra Gets Revised 8-Speed Automatic Transmission

GM intends to pair the revised Hydra-Matic 8L80 eight-speed automatic transmission with one of the engines available for the 2024 GMC Sierra 1500 pickup, sources familiar with the matter have informed GM Authority. 

The 2024 GMC Sierra 1500 trucks motivated by the turbocharged 2.7L I4 L3B gasoline engine, now known as the TurboMax, will now transmit power to the wheels via the second-generation Hydra-Matic 8L80 eight-speed (RPO code MFC). The L3B engine is fitted as standard in Pro, SLE and Elevation trim levels.

The all-new 2023 Chevy Colorado is another GM truck outfitted with the revised Hydra-Matic 8L80 transmission, providing a closer look at the transmission in a current-production vehicle. GM selected the 8L80 eight-speed transmission instead of its 10-speed automatic because the L3B engine generates strong torque, removing the need for two additional gear ratios.

In fact, the ratios of the Hydra-Matic eight-speed match up well to the performance of the turbocharged 2.7L engine. The three other available 2024 GMC Sierra 1500 engines will continue to use the widely-equipped GM 10-speed automatic transmission.

The revised Hydra-Matic 8L80 replaces the previous eight-speed transmission build (RPO Code M5T) equipped in 2019 through 2023 GMC Sierra 1500 units. Over the years, GM’s eight-speed caused several lawsuits to be filed against the automaker. These suits claimed these transmissions made the vehicles jerk, hesitate, surge, or lurch during driving. The plaintiffs also alleged the release of 60+ technical service bulletins and updates shows GM knew about the transmission’s problems since 2013.

Alex Luft, GM Authority Executive Editor, recently test-drove a pickup outfitted with the new Hydra-Matic 8L80 eight-speed transmission. His conclusions were that the transmission is “very good,” providing mostly reliable function and good shifting. However, he found accelerating rapidly from a speed of 5 to 10 mph still produced a jarring surge, while at higher speeds the transmission occasionally held shifts longer than necessary.

As a reminder, the GMC Sierra 1500 is available with four powertrain options. These include the turbocharged 2.7L I4 L3B gasoline engine, rated at 310 horsepower and 430 pound-feet of torque (and now paired with the Hydra-Matic 8L80 eight-speed), the naturally aspirated 5.3L V8 L84 gasoline engine developing 355 horsepower and 383 pound-feet of torque, the naturally aspirated 6.2L V8 L87 gasoline engine producing 420 horsepower and 460 pound-feet of torque, and finally, the 3.0L I6 LZ0 turbodiesel Duramax, rated at 305 horsepower and 495 pound-feet of torque.

The turbo-diesel mill was updated for the 2023 model year, replacing the LM2 that was available for the 2019, 2020, 2021 and 2022 model years.

GMC logo on a 2024 GMC Sierra grille.

Under the skin, the 2024 GMC Sierra 1500 rides on the GM T1 platform. The start of regular production (SORP) for the truck’s 2024 model year is scheduled for July 17th, 2023. The Sierra 1500 will continue to be produced at the GM Fort Wayne plant in Indiana and GM Silao plant in Mexico. Dealers can begin ordering new units starting in June.

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Comments

  1. There goes GMC copying Chevrolet again… or is it Chevrolet copying GMC?… It’s almost like the Sierra and Silverado are the same thing…

    Wonder why they don’t write 1 story talking about both trucks getting the same thing.

    Here’s an idea. They should leave the Chevy news free and start charging a subscription to read the GMC news. That will differentiate them more and make the GMC more professional grade.

    Reply
    1. They are the same and have been for decades. The sheet metal and interiors are different but the rest is the same.

      Reply
  2. Good luck!

    Reply
  3. Releasing a transmission that is “mostly” improved is still unacceptable. If your writer identified these conditions in a newly built truck, what will owners find after they have put a few thousand miles on their vehicles. GM has a proving grounds and labs where these transmissions can be tested and verified as reliable. Releasing them to consumers to be their guinea pigs is ridiculous.

    I find it dumbfounding that GM doesn’t understand why it is losing sales of mid and full size pickups, when the transmissions in these vehicles is the elephant in the room.

    Reply
    1. As free, I know people today who will not buy another GM because of transmission problems that GM refused to handle.

      Reply
      1. Mary does not care

        Reply
  4. Are there any engine changes between the 2023 and the 2024 GMC sierra 1500 Denali ultimate?

    Reply

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