A machine that’s truly ready for anything
Last year, I drove a GMC Sierra 2500 AT4X all over the trails of Moab, Utah, so I can attest that taking any heavy-duty pickup truck off-road is a bit of an event. The sheer size and weight of the vehicle make for challenges in places where Jeeps would skamper through. Still, I was truly impressed with its off-road capability and comfort, and pondered the potential for a truck like this becoming a serious overlander.

Overland Expo
There are different definitions as to what overlanding actually is. Initially, the idea was to cross terrain and spend time in remote locations while being entirely self-reliant. It’s like camping, serious off-roading, and living off the grid all in one. Additionally, the rig needed has to be capable of long-range driving, off-road toughness, and serve as a base for your remote adventure.
The powertrain is a big bonus
Having a diesel helps, but longer ranges and the ability to tow more are big bonuses, and the GMC Sierra 2500 AT4X Ultimate Overland Build comes with a 6.6-liter Duramax turbo-diesel that makes a massive 470 hp and 975 lb-ft of torque. It’s equipped with a 10-speed Allison transmission, and given its 38-gallon fuel tank, it’s estimated to have a range of approximately 500 miles, depending on the terrain. The standard AT4X’s tow rating is around 18,000 lbs, which is more than adequate for a larger off-road trailer. Payload sits at about 2,600 lbs, but given the slide-in camper, extra overlanding components, and gear, it’s significantly less in this build.
The 2024 GMC Sierra AT4X offers 120-volt power outlets with a capacity of 400 watts on the instrument panel and inside the cargo bed. Being that it’s a diesel pickup (a less powerful gas engine is available), it can chug along idling all day, serving as a generator as needed, without burning too much fuel. Additionally, from the cockpit, the Duramax is one of the quietest diesels I’ve ever tested.

The “Ultimate Overland Build”
Starting with the 2025 GMC Sierra 2500HD AT4X, which already has a beefed-up suspension, rear locker, and a ton of armor, American Expedition Vehicles (AEV) in Michigan added the following to the build:
● AEV Salta XD Wheels paired with 37” BFGoodrich All-Terrain KO2 tires
● AEV 37” Tire Clearance Kit
● ComeUp SOLO 12.5rs winch, co-developed with GM
● AEV Snorkel for cleaner, cooler airflow
● AEV Front Bumper Light Bar (prototype) with Vision X Explora off-road lights
● AEV Paint Appearance Package
● Magnaflow stainless steel exhaust for increased efficiency
● Air Lift LoadLifter 5000 Pro suspension kit for camper-readiness

The OEV Back Country slide-in truck camper, which offers four-season capability and R8 insulated composite walls, has its own off-grid system that includes:
● 220W solar panel and 270Ah lithium battery
● Truma heating/hot water system
● Xantrex inverter, Isotherm fridge, and 20-gallon water tank
● Alu-Cab 270 awning, shower cube, and premium storage solutions
The build was then brought to Tiny Rig Co. in Westminster, CA, who wired auxiliary lighting and installed a Switch-Pros SP9000 system. Other accessories include:
- Switch-Pros SP9000 system
- Tackform TRAXX system for in-dash device mounting
- ONWRD Supply Co. seat back organizers
- Viair portable compressor and Rig Ready Systems Jackout HD kit
- Redzone Wireless internet and Zoleo Satellite Communicator for global connectivity
- onX Offroad and a Midland CB radio
- Opinel USA
- Forrest Tool Company Tool Kit
- Lavabox Portable Campfire

Overland Expo
Driving this beast is easier than you think
Amid the typical L.A. traffic, the ride was remarkably serene. That air suspension was dialed in to the point where the vehicle was luxury-car smooth on many surfaces. Throttle response is surprisingly quick for something that weighs as much as a Sherman Tank, and it handles its girth with ease around corners. I took it deep into the mountains around Rancho Palos Verdes, and along several back highways. Stopping at various ocean overlooks, I was able to spend time enjoying the overall comfort of the vehicle.
In recent days, I’ve driven a few 1500 pickup trucks that are lighter and smaller, yet they didn’t feel that much smaller in traffic. Honestly, only two issues were noticeable to me behind the wheel. The digital rear-view camera wasn’t relocated, and there was some hesitation in the steering. I suspect the steering system is heavily taxed moving such heavy rubber, and it was a bit slow to swing side to side. Otherwise, the truck was a joy to drive and made most other trucks look puny to me, in more ways than one.
Overland Expo 
Final thoughts
I know I didn’t deep dive into the convenience of the slide-in, pop-up camper. There’s enough room for three to sleep, as long as two of the sleepers don’t mind sharing a queen-size mattress. Otherwise, there’s a good-sized fridge, sink, stove, and provisions for plenty of dry-good storage. The external shower can double as a good location for a porta-potty, and there’s a shade that extends around a majority of the living quarters. Weekend camping should be a snap, and serious overlanding is something this rig was built for.
I’m sure the price tag for a build like this could easily exceed $250,000. I’m guesstimating that the truck’s cost (about $96,000) and the slide-in camper (about $50,000) are the most expensive major bits. Still, it’s all the smaller components and the labor required to install everything that adds a ton to the build. Lighting, solar, showers, awning, air suspension, winch – the list of addons goes on and on. As such, adding $100,000 to the price is what got my estimate to $250,000. Even then, I might be undercutting the total by a bit.
If all of this sounds like the build for you, you might be in luck. The “Ultimate Overland Vehicle Build” will be auctioned off on Bring a Trailer in November, with all proceeds benefiting the Overland Expo Foundation. If you’re drooling at the thought of owning this AND you want to help out a great cause, we’d keep an eye on the Overland Expo Foundation Facebook page.




























































































