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The GMC Sierra 2500 AT4X gets the poseurs dirty

The 2024 GMC Sierra 2500 AT4X is the Swiss Army Knife of pickup trucks, and its added off-road ability makes it huge fun.


If everyone could see your washer and dryer, imagine the baubles that would suddenly adorn them. Alas – they remain hidden in the safety of your home, slowly sacrificing themselves to ensure your unmentionables become mentionable. And yet, we can run this experiment on something with wheels – the GMC Sierra 2500 AT4X.

How? Simple – for all the Cybertrucks and Hummer EVs out there (so about 5), there are a million ancient Silverados and Sierras, hauling and ensuring you can live your life just a bit more easily. They are full of crust, rust, and history.

Here we come, you and I, in our shiny sports cars as we pass them on the highway at supersonic speeds with nary a second thought. At least, we used too, because now pickup trucks are as fancy as any luxury car inside and out. And as powerful.

Since when did pickup trucks become fashion statements?

GMC Sierra AT4X

2024 GMC Sierra 2500 AT4X AEV Quick Take

Get one:

995 lb-ft of torque. Long range. Easy to live with. Crushes everything in its path.

Don’t get one:

Awkward shifter. Clangs over bumps. Loves to drink, even if you don’t tow anything. Nearly double the base price with options.

Soul Score: 7

Not just a toy, and more than a fashion statement, this Sierra is built to run over poseurs.

The GMC Sierra 2500 AT4X Overview

GMC Sierra AT4X
Fits right in.

Cars have always been, and always will be, a fashion statement first and foremost. People judge you on your first impression, be it clothes or cars.

GMC acknowledges this, so there are a million ways to configure your Silverado. Err, Sierra. They might fulfill the same purpose, but if the Silverado is more Cuisinart, this Sierra is Viking. All the bells and whistles. Luxury, power, ability. And chrome. Lots of chrome. Not for our mean AT4X though because GMC was asked to tone it down a bit.

GMC Sierra AT4X

There’s a diesel under hood (a $9,490 option), and a level of technology almost on par with the amazing Hummer EV. It is truly a Swiss Army knife for the road. Short bed, long bed, double cab. Ahem…22,500 pounds of towing ability.

Still, some sins of the past are hard to shake. Let’s see which ones remain.

Performance Score: 8. Good luck, Cybertruck

GMC Sierra AT4X
Electric trucks are still toys by comparison

You can get in this GMC Sierra 2500 AT4X, attach an aircraft carrier to the back, point it toward the nearest mountain, and laugh manically like the Joker.

Well, maybe not. But after driving around in it all week, I can tell you that electric pickup trucks have a long way to go, because this combination of power and off-road ability are unmatched by anything with a battery.


GMC Sierra AT4X
Nearly 1,000 lb-ft awaits.

Diesel isn’t dead, despite what the Europeans have you believe. Under this hood is a 6.6-liter turbo-diesel V-8 with 445 horsepower and 995 lb-ft or torque. It’s Hell Yea, ‘Murica, with George Washington riding a bald eagle while shooting down terrorists.

Unladen, the Sierra is genuinely quick, reaching sixty in about six seconds but feeling like it’s half that because this is a gigantic thing that punches a serious hole through the fabric of space and time. The Sierra starts to run out of steam at speeds above 80, or maybe it was me saying “Okay, yup, I’m good now.”, because I felt like a freight train engineer.

GMC Sierra AT4X
Hood scoops are cool.

Being diesel, you don’t need to rev – all that twist is available pretty much off idle. Loud too. Not Ram TRX loud, it’s more refined than that. But gun it and hear a staccato roar through the gigantic tail pipe.

No way I consider the gas option V-8, with its whimpy 464 lb-ft of torque. Well, maybe if you don’t need to tow a lot, because this does add nearly $10,000 to the bottom line.


GMC Sierra AT4X
This shift lever still feels old-school.

Here we have an Allison 10-speed automatic, and if the name sounds familiar, it’s because they also make transmissions for tractor trailers (this a big boy). It shifts with impressive smoothness and quickness, never drawing attention to itself. Also impressive is an engine brake feature, useful for helping to slow the Sierra when towing downhill. Not sure why I expected it to make the GMC sound like it had a Jake Brake.

There’s also four-wheel drive with an off-road mode and a computer smart enough to know when you need it – you.

GMC Sierra AT4X
Come on…no one noticed this before approval?

The shifter itself lives on the steering column, but I admit that I hate it. First, it’s gigantic and blocks your view of the infotainment screen – I mean really blocks it, so you can’t see useful info like oh, where you’re going. It’s also a bit awkward to pull into drive and reverse, making you guess. Feels old school and out of place in such a high-tech truck.

Would be better to move the shift function over to the center console (there’s room, trust me), and just make it a toggle switch like on a 5 Series.

Steering and chassis

GMC Sierra AT4X
Heavy, but still direct for a truck this size.

I want to dispel any notion you may have of this being a slovenly, loose, or messy truck. The only thing that makes it a handful is sheer size.

Start with steering. Grip a big wheel and turn to find a fair amount of effort needed. It’s not a bad thing – this is a big truck with gigantic tires, after all. Aside from a soft spot right off center, I’d say this Sierra is easily controlled. GMC was the only major American company to have four-wheel steering on its pickup trucks in the early 2000s. Dubbed Quadrasteer, it’s long since disappeared from the Sierra’s menu. A shame, because the Hummer makes good use of it.

GMC Sierra AT4X
Four-wheel drive and a two-speed transfer case help keep it all under control.

On-road, I wouldn’t call it smooth over bumps and cracks in pavement, though I think it’s perfectly livable. If you want a better ride, go with a Denali.

The chassis is set up for off-road use, with the AT4X AEV trim getting 35-inch Goodyear MT tires, a 1.5-inch lift, steel skid plates and Multimatic dampers. Going deep into dirt, mud trails and wooded areas, the Sierra’s ride became serene, and its steering perfect at communicating how much grip was available.

GMC Sierra AT4X
Multimatic dampers.
GMC Sierra AT4X
Four-wheel drive and trailer modes.

Though you must get the AT4X trim to obtain them, the Multimatic dampers once again perform GM magic and make it worth the price if serious dirt is on your menu.


GMC Sierra AT4X
Brakes are hidden behind 18-inch wheels.

Perhaps one area where it’s apparent that this is a pickup truck is the brakes. They work well enough, but if you need to panic brake at all the pedal becomes very firm, as if the Terminator’s hand is holding the pedal. With 8,200 pounds to stop, you must be aware that plenty of room is needed to halt this thing, more so if you’re carrying a load.

GMC Sierra AT4X
The performance is there.

This is a high-performance vehicle, and like other machines that make you go “whoa, bro!“, convenience and cost are not always first considerations. The GMC Sierra 2500 AT4X looks the part, but more importantly has the chops to let you explore Mars if there was an atmosphere on it.

Utility score: 10. The bro box

GMC Sierra AT4X
A spray-on bedliner comes from the factory.

I gotta start here in the bed. It’s gigantic, with a power tailgate and factory liner to protect your precious paint (and there’s still a longer bed if you need more room). There are side steps to make it easier to place things inside, since the truck is nearly as tall as I am, and bottom step runners that motor out of the way to clear off-road obstacles when you’re inside are a requirement. Imagine if they fail to pop out the one time your 5’2 wife borrows your truck.

GMC Sierra AT4X
Steps are definitely required, given the height.

And how about the face I made as I discovered what I shall call: the Bro Box. Lift a small panel on the tailgate door, and it reveals a 120-volt outlet to charge your electronics, and speakers! Would make an awesome tailgate truck. GMC – send me one for football season!

GMC Sierra AT4X
Bro box!

Inside, the Crew Cab is just as convenient and useful. Select the Regular or Double Cab if you want more gear and less friends. The front seats are simple in shape but fit my size quite nicely – even the bottom cushion is long enough. The rear too, offers plenty of legroom and enough headroom for your pet giraffe. You might find that typical GM-plastic paneling, but it bothers me less here than in a Cadillac. Looks like it’s meant to get dirty, so just wipe it clean and off you go.

GMC Sierra AT4X
The seats are quite comfortable.
GMC Sierra AT4X
The rear bench has enough room to fit three.

The GMC Sierra 2500 AT4X Crew Cab will absolutely take up two parking spaces, and probably won’t fit in your garage. Decide if you need the size and select your Sierra accordingly.

Fuel Economy: 7. Pass gas (stations)

GMC Sierra AT4X
600 miles to the tank is no joke.

I drove the Sierra nearly 500 miles in a week, and I did not put a drop of diesel in it. You can easily get 600 miles to the tank. For this distance, you must pay – a 36-gallon fuel tank is aboard, and I was barely able to achieve more than 13 MPG.

GMC Sierra AT4X
I averaged 12.7 MPG during my time.

But I can’t knock this car because of it. Unlike say, a supercharged E92 M3, we’re not using dead dinosaurs for fun and frivolity. You need to tow things and carry a lot of crap? No other way to do it. And it’s here I’ll mention the Cybertruck and Hummer EV. They have less than half the range and towing ability – and for a lot of people that’s not a spec sheet line. It’s their life.

Diesel is a more efficient option than gasoline in this case, and provides another reason to spend the nearly $9,000 difference.

Features and Comfort: 8. Lux lite

GMC Sierra AT4X

While it might cost a lot, GMC gives you everything you could possibly want. It’s also a vehicle that, with absolutely no options selected, costs $47,395, and that makes it tough to cater to both areas of the market.

Hose it off

GMC Sierra AT4X
Inside: many buttons.

I hate listing the brochure, so rest assured that everything from a power-sliding rear glass tailgate window, to ventilated front seats and all the safety features you could want is here.

Ah, well almost. First, a few things that aren’t here include a decent infotainment screen. Look inside a RAM to see how it can be done, because the Sierra’s 13.4-inch screen is so narrow that it becomes hard to read. This is a gigantic truck, it needs something more substantial. Another issue was the headlights, or lack thereof. Despite them dominating the front-end, I found that driving at night to be a perilous experience – they don’t really shoot light out far enough. GM has had this issue on their pickup trucks for awhile now, so I’d say it’s time for a rework.

GMC Sierra AT4X
The nav screen is both long and thin.
GMC Sierra AT4X
The center stack has many buttons of varying textures.
GMC Sierra AT4X
Leather, but easily cleanable.
GMC Sierra AT4X
AEV trim gets embroidered headrests.

Some might point to the cheap-feeling bits on the inside, but while it’s no G-Wagon, I don’t mind so much here. I got the inside filthy, and it’s a lot easier to hose down rubber than cut-pile carpet.

There are a ton of buttons and dials inside to help you control everything – it takes a minute to get used to where everything is.

We outside

GMC Sierra AT4X
This is a large truck. Very large.

Things like gigantic power-everything side-view mirrors and a spray-on bedliner are what you expect in a truck like this. Opting for the AEV trim gets you unique stamped steel bumpers, gloss black door handles, and glass black 18-inch wheels.

Grunts in approval.

The GMC Sierra 2500 AT4XBut I must say I prefer the RAM TRX look – all flared fenders and macho colors. The Sierra is a more conventional truck and looks it, though you still get a gigantic hood scoop and DURAMAX diesel badge in case you forget which one is yours.

GMC Sierra AT4X
These don’t work very well.
GMC Sierra AT4X
Power running boards are important – it’s impossible to get in without them.

There’s also tons of bed lights to help you see in and around the truck (ironic since the headlights aren’t great), and enough cameras to help you tow the space shuttle out of storage. We sometimes balk at the price of a vehicle, but in the case of the Sierra, $103k gets you a lot of hauling help instead of soft leather or sexy fender flairs, and it’s the right choice.

The GMC Sierra 2500 AT4X is a justifiable toy

GMC Sierra AT4X

Like Shrek insisting that Lord Farquaad is overcompensating because of the size of his castle, so too must owners of this Sierra beware that some may give you severe side eye for this purchase.

You should not care. The Sierra with a diesel engine makes more sense than a majority of other pickups, and its off-roading ability increases the fun factor. Just how much ability if up to you, because this fully-loaded to the brim AEV example comes in at $103,075. You could probably do without the skid plates and other (admittedly fun) AEV-branded things and have a regular AT4X for nearly $10,000 less, but if you come this far, you might as well.

GMC Sierra AT4X

You can go even bigger – dually wheels with the 3500 HD model, or the more pedestrian 1500, with unpainted bumpers and steelies. It’s probably safe to say that a good amount of people who opt for this 2500 AEV edition won’t actually use it as GM intended, but it always looks like it could take you on an adventure. Maybe that’s what matters.

So that’s what a washing machine looks like when everyone can see which one you have…

GMC Sierra AT4X

2024 GMC Sierra 2500 AT4X Specifications

Vehicle Type: Front-engine, rear- or four-wheel drive, five-passenger, four-door pickup truck.


Base: $81,800
As tested: $103,075


6.6 liter Turbo-Diesel V-8
445 horsepower @ 2,800 RPM
910 lb-ft @ 1,600 rpm RPM


Wheelbase: 158.9 in
Length: 250.1 in
Width: 81.9 in
Height: 79.8 in
Curb Weight: 8,260 lbs


Combined / City / Highway: 28 / 26 / 33

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