First Drive: 2024 GMC Sierra 2500 HD AT4X AEV

First Drive: 2024 GMC Sierra 2500 HD AT4X AEV

by Michael Satterfield - Photo by Lucas Kepner - 03/29/2024

Texans have a love for big trucks, but the 2024 GMC Sierra HD AT4X AEV is so colossal that it might not be the right choice unless you're planning an extreme off-road expedition that also requires the ability to tow a massive 18,400 pounds. However, you might find it challenging to navigate tighter trails. Like most off-road vehicles, the AT4X AEV Sierra will likely spend most of its time in suburbia. 

The American Expedition Vehicle (AEV) package takes the already off-road-ready Sierra HD ATX4 and adds a lot more features than just some badges. The AEV gets the same 1.5-inch suspension lift as the HD AT4X but thanks to the Multimatic DSSV spool-valve dampers, it rides more like a luxury car than an off-road pickup. AEV 18-inch aluminum wheels get wrapped in 35-inch Goodyear Wrangler Territory MTs. Outside the truck gets stamped steel front and rear bumpers with heavy-duty recovery points, and the front bumper is winch-ready. The chassis, fuel system, and drivetrain are protected with five boron steel skid plates and rocker panel protectors. Of course, it also gets some style accessories, such as a blacked-out grill, door handles, and rear tailgate decal. You'll also find AEV logos on your headrests and floormats.

Read Our Review Of the GMC Sierra 1500 AT4X AEV 

First Drive: 2024 GMC Sierra 2500 HD AT4X AEV Wheels

The Sierra 2500 HD AT4X AEV comes exclusively as a 2500HD crew cab with a six-foot-nine-inch bed and four-wheel drive. Buyers can choose between a gasoline-powered 401-hp 6.6-liter V8 with 464 pound-feet of torque and a 470-hp turbocharged 6.6-liter V-8 Duramax diesel packing 975 pound-feet of torque. Both powerplants put power to the ground through a 10-speed automatic transmission and the 2-speed Autotrac electronic transfer case. Our test vehicle had the standard diesel, which is the right choice, and it returned an average of 18 MPG with a lot of highway driving.

Texas doesn't have any significant mountains to test on, but we did hit some trails, and we found that nothing we threw at it even phased it. While on paper, it would be great to take this truck to Moab and go exploring, I know that its size and weight would be its most significant limitations in doing some wild off-roading. If towing isn't your concern, and you want to hit the trails, you should look at the GMC Canyon At4X AEV to be the go-anywhere vehicle. The Sierra is the "go-most places" vehicle, just not on tight trails or low parking garages.

First Drive: 2024 GMC Sierra 2500 HD AT4X AEV

Inside, the Sierra is still our favorite luxury truck, offering incredible comfort, intuitive technology, and all of the features you would expect in a truck that costs over $100,000. Yes, the 2024 Sierra 2500 HD AT4X 4WD AEV we tested comes in with an MSRP of $104,520. So, you have to choose between making a payment on a lake house or making a payment on a truck to tow your boat to the lake. 

Check out more specs below or visit GMC.com to build your own.

First Drive: 2024 GMC Sierra 2500 HD AT4X AEV

ENGINES

Type:

6.6L V-8 gasoline or E85 FlexFuel

Bore & Stroke       (in / mm):

4.06 x 3.86 / 103.25 x 98

Block Material:

Cast iron with nodular iron main caps

Cylinder Head Material:

Cast aluminum

Compression Ratio:

10.8:1

Valvetrain:

Overhead-valve, two valves per cylinder, variable valve timing

Fuel Delivery:

Direct fuel injection

Horsepower
(hp / kW @ rpm):

401 / 299 @ 5200 (SAE certified – gasoline)

Torque
(lb-ft / Nm @ rpm):

464 / 629 @ 4000 (SAE certified – gasoline)

 

Type:

Duramax 6.6L V-8 Turbo-Diesel

Bore & Stroke         (in / mm):

4.05 x 3.89 / 103 x 99

Block Material:

Cast iron

Cylinder Head Material:

Cast aluminum

Compression Ratio:

16.0:1

Valvetrain:

Overhead-valve, four valves per cylinder

Fuel Delivery:

Common-rail direct fuel injection

Horsepower
(hp / kW @ rpm):

470 / 350 @ 2800 rpm

Torque
(lb-ft / Nm @ rpm):

975 / 1322 @ 1600 rpm

TRANSMISSION & AXLE

Type:

Allison® 10L1000 10-speed automatic

Gear Ratios (:1):

 

     First

4.54

     Second

2.87

     Third

2.06

     Fourth

1.72

     Fifth

1.48

     Sixth

1.26

     Seventh

1.00

     Eighth

0.85

     Ninth

0.69

     Tenth

0.63

     Reverse

4.54

Final Drive Ratio:

3.73 (6.6L gas)

3.42 (6.6L diesel)