When it comes to high-end heavy-duty trucks, GM has thrown down the gauntlet for 2024. If you are in the market for the absolute best in towing capability, luxury, and off-road performance, you have likely narrowed it down to two heavyweights: the Denali Ultimate and the AT4X.
Both of these trucks are fitted with the legendary Duramax diesel engine, but they serve very different masters. One is the undisputed King of the Road, dripping in chrome and leather. The other is a factory-lifted trail warrior designed to conquer any terrain.
In this review, we’re breaking down the differences between these two titans to help you decide which one deserves the spot in your driveway.
The Powerhouse: 2024 Duramax Diesel
Before we look at the trims, let’s talk about the heart of the beast. Both of these 2024 models are powered by the updated 6.6L Duramax Turbo-Diesel V8.
While previous generations were impressive, the 2024 refresh brings the numbers up to 470 horsepower and a massive 975 lb-ft of torque. Whether you choose the luxury cruiser or the off-road bruiser, you are getting the same massive towing capability and raw power under the hood.
The Contender #1: 2024 Denali Ultimate
The King of Luxury
The Denali Ultimate is designed for the driver who wants a truck that looks as good at a black-tie event as it does pulling a fifth wheel. It is the pinnacle of GM’s interior design and comfort.
Exterior Styling
The first thing you notice is the "Vader Chrome" or tinted chrome finish. It’s significantly darker and moodier than the traditional bright chrome found on standard Denalis.
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Signature Details: You’ll find topographical maps of the Denali mountain range laser-etched throughout the truck, including the badges.
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Lighting: Full LED headlights and fog lights with painted-to-match surrounds.
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Convenience: Standard power-retractable running boards with LED lighting and a chrome edge—clean, functional, and classy.
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The Bed: It comes standard with the Multi-Pro tailgate and the built-in Kicker Bluetooth audio system (a great feature for tailgating, though it operates independently from the truck's main stereo).
The "Ultimate" Interior
This is where the Denali Ultimate separates itself from the pack. The interior is arguably the most comfortable heavy-duty cabin GM has ever produced.
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Alpine Umber Interior: A rich, chocolate brown full-grain leather with white piping and baseball stitching.
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Genuine Materials: Real open-pore Paldao wood trim (also featuring the topographical map etchings) and a suede headliner.
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Comfort: 16-way power front seats with massage functionality are standard.
Verdict: If you spend long hours on the highway hauling heavy loads and want maximum comfort, the Denali Ultimate is hard to beat.
The Contender #2: 2024 Sierra 2500 AT4X
The Off-Road Warrior
New for the heavy-duty lineup in 2024, the AT4X trim takes the off-road capability of the standard AT4 and dials it up to eleven. This is a factory-built rig ready for the trail immediately off the lot.
Exterior & Suspension
The AT4X stance is noticeably different. It commands presence, not through chrome, but through height and aggressive geometry.
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Factory Lift: It comes with a 1.5-inch factory suspension lift and larger 35-inch Goodyear Territory MT tires.
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Multimatic DSSV Dampers: This is the secret sauce. These spool-valve shocks provide incredible on-road comfort while being able to handle high-speed off-road punishment. They virtually eliminate the "empty truck hop" you feel in standard heavy-duty trucks.
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Bumpers: High-clearance front and rear bumpers and stamped steel skid plates protect the vitals.
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De-Chromed Look: The AT4X features almost zero chrome. The door handles, grille surrounds, and body moldings are all body-color or black for a menacing, stealthy look.
The "Obsidian Rush" Interior
While it is an off-road truck, you aren't sacrificing luxury. You still get the massive 13.4-inch touchscreen, heads-up display, and sunroof.
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Style: A Jet Black full-grain leather interior with white piping and red stitching gives it a sportier, more technical vibe compared to the Denali’s warm luxury.
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Tech: It includes the all-important rear e-locking differential button, a must-have for serious off-roading that you won't find on the Denali.
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Massage Seats: Surprisingly, even the rugged AT4X comes with massage seats standard.
Verdict: If your lifestyle involves hunting camps, job sites with rough terrain, or you just prefer the lifted, aggressive look without voiding your warranty, the AT4X is the winner.
Price & Market Value
Interestingly, while the AT4X has a slightly higher MSRP (often pushing $98,000+ due to the expensive suspension and off-road equipment), the Denali Ultimate often commands a similar price point due to high demand for its luxury features.
In the pre-owned market, you might find deals on low-mileage examples of both, but expect the AT4X to hold value well due to its unique status as the supreme off-road heavy-duty truck.
Which One Should You Buy?
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Buy the Denali Ultimate if: You want the status symbol. You love the "Vader Chrome" aesthetic, the warm brown leather interior, and you stick mostly to pavement and towing.
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Buy the AT4X if: You want the best riding suspension GM offers (thanks to those Multimatic shocks), you need a rear locker for tough terrain, and you prefer a blacked-out, aggressive stance.
Check out the full in-depth video walkaround below to see the interiors up close!
https://www.youtube.com/watch?v=RJzikEujwCo