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A white 2024 GMC Sierra 1500 SLE is shown parked on grass.

The 2024 GMC Sierra 1500 AT4X Gets a Capable New Engine

If you’re looking to head off-road in a rugged truck, then this is a great time to be shopping for a new ride. In the past, you had to customize your truck with pricey and finicky accessories in order to make it ready to tackle the trails. These days, there are plenty of trim levels that roll off the factory floor ready to take on rough terrain. As these rugged trucks get more and more popular, the automakers that produce them are always working to provide more capable options to off-road enthusiasts.

For example, the GMC Sierra used to have a single dedicated off-road trim, the AT4. For the 2022 model year, the automaker unveiled an even more capable option, the AT4X. For 2023, the AT4X got an AEV Edition with special equipment from American Expedition Vehicles, adding skid plates, exclusive styling features, and steel bumpers with recovery points. Now, GMC has announced that the 2024 GMC Sierra 1500 AT4X will have a new standard powertrain, with a Duramax Turbo-Diesel engine under the hood.

If you’re considering getting the latest version of the AT4X, then you should know how this change will affect your experience as a driver. Today, we’re going to go over how this powertrain differs from what was available on the 2023 model and what you need to know if you’re thinking about buying a 2024 AT4X. If you’ve never had a diesel truck before, don’t worry. We’ll go beyond the horsepower and torque numbers and look at the advantages and disadvantages of diesel over gasoline.

A silver 2024 GMC Sierra 1500 is shown driving on a highway.

Engine Options on the 2023 Sierra 1500 AT4X

For the 2023 model year, the Sierra 1500 AT4X was available with just one type of engine, a 6.2L EcoTec3 V8. Other Sierra trims feature a less powerful 5.3L V8 that produces 355 horsepower and 383 lb-ft of torque. The beast under the hood of the 2023 AT4X, on the other hand, can provide 420 horsepower and 460 lb-ft of torque. The engine features dynamic fuel management technology to keep you from burning more fuel than necessary. It pairs with an electronically controlled 10-speed automatic transmission, and features powertrain grade braking to reduce wear on the brakes while driving downhill.

The New Duramax Turbo-Diesel

GMC’s recently updated 3.0L Duramax Turbo-Diesel engine will now be the standard option for the 2024 Sierra 1500 AT4X. This engine was introduced to select trims of the 2023 Sierra 1500, and has proved to be a powerful option, leading to GMC equipping the rugged off-road AT4X with it. The latest version of this engine benefits from a variety of recent upgrades, including new steel pistons and fuel injectors, a revised combustion bowl, a retuned turbo compressor, and updated temperature control features to keep the engine running strong without overheating.

These recent developments have made the powertrain more useful for off-roading, which can put a lot of strain on an engine. While diesel has a reputation for being loud and rough, GMC has worked to make this new option smooth and quiet, so it has decent on-road manners as well as rugged off-road capability. That’s good news for drivers who need to take a trip down the highway in order to get to the trail.

When it comes to power, the Duramax engine delivers 305 horsepower. That may be less than the gas-powered V8 can produce, but it’s plenty for reaching thrilling speeds in the great outdoors. Perhaps more important is the engine’s maximum torque of 495 lb-ft. That’s a significant upgrade over the V8, and the best of any of the Sierra’s available engines. On top of having an impressive maximum torque figure, the diesel engine also provides solid low-end torque, which is vital for off-road activities like boulder crawling.

A white 2024 GMC Sierra 1500 AT4X is shown driving off-road.

Diesel vs. Gasoline

While gasoline and diesel are pretty similar on the surface, they do have a fair amount of differences. For one thing, gasoline is clearly the more popular of the two. Even if you’re going to fill up your diesel engine, you’ll be heading to the “gas station,” after all. The fact that early diesel engines were loud, rough, and emitted a lot of smog probably helped gasoline get the upper hand. Gasoline also has a lower freezing point, allowing it to get to colder temperatures without solidifying.

However, many of these advantages of gasoline are less of a concern in the modern day. Diesel engines have come a long way, and now run more smoothly, quietly, and cleanly. Features like engine warmers have made freezing temperatures less of a problem, and the introduction of bio-diesels has made the fuel less of a concern for the environment.

Diesel also has a fair number of advantages over gasoline. For one thing, diesel engines tend to have fewer components, which means that they generally don’t require as many repairs as their gas-powered counterparts. Diesel also holds more energy per part than gasoline does, making it more efficient.

Aside from diesel’s excellent towing capabilities, its biggest advantage is fuel economy. Let’s take a look at the EPA’s estimates for the 2023 Sierra AT4X. With the 6.2L V8, the truck gets a combined rating of 15 MPG and a total range of 360 miles. The 3.0L diesel engine gets 19 MPG combined. Even though its fuel tank is exactly the same size as its gas-powered counterpart, it has an estimated 528 miles of total range. The first figure means less pain at the pump, but the second may be even more important to off-roaders who are driving off into the wilderness, where there aren’t many gas stations. A rugged trail in the woods is a terrible place to find that your fuel tank is empty.

Other AT4X Changes

The change to the AT4X’s standard powertrain is the most significant update for the 2024 model year, but it’s not the only one. Along with the Denali, Denali Ultimate, and AT4 trims, the AT4X will be getting new power retractable assist steps, which help drivers and passengers get into the cab but don’t detract from the truck’s aerodynamics while they’re tucked away. An available active exhaust will also be available for these trims, along with the SLT. On top of that, GMC is adding two new exterior paint colors to the lineup, Downpour Metallic and Thunderstorm Gray.

Some Final Thoughts

For the 2023 model year, the Sierra AT4 could be had with either the diesel engine or the gas-powered V8, while the beefier AT4X was only available with the V8. This change to the lineup allows drivers to get behind the wheel of the most off-road-ready Sierra around with a diesel engine under the hood. While some may be disappointed to see the horsepower figure fall, many off-roaders are sure to embrace the AT4X’s new base powertrain.

The higher torque figure, and especially the improved low-end torque, provide power where those tackling rocky trails need it most and the extra range means that drivers can go deeper into the wilderness without worrying about an empty tank. The trim’s equipment otherwise remains basically the same, which makes sense since the AT4X is only a few years old and already comes loaded with tough skid plates, electronic-locking differentials in the front and rear, and huge wheels fitted out with all-terrain tires. This new engine is just the cherry on top. However, if you still prefer gasoline to diesel, the 6.2L V8 is still available as an option. The AT4X now lets you choose the best option for your needs.