Now in its fifth year, Overland Expo’s renowned Ultimate Build program continues its tradition of transforming capable factory vehicles into elite overland rigs. For 2025, the spotlight is on the all-new GMC Sierra 2500 HD AT4X American Expedition Vehicles (AEV) Edition, a powerhouse that seamlessly blends rugged off-road capability, advanced technology, and premium comfort. This formidable platform is paired with the Overland Explorer Vehicle’s (OEV’s) Back Country 6.85, a slide-in truck camper, resulting in the ultimate overland adventure vehicle.
The rig’s debut showing will take place at the 2025 Overland Expo West in Flagstaff, Arizona, May 16-18, only a few weeks away.
Engineered for overland travelers who demand uncompromising capability and reliability, the 2025 GMC Sierra 2500 HD AT4X AEV Edition is a purpose-built platform ready for long-distance expeditions and extreme terrain. Built on a high-strength, fully-boxed steel frame, it features revolutionary Multimatic DSSV dampers, which are race-proven shocks offering unparalleled ride control across varying terrain. Complemented by electronic locking differentials, factory-installed AEV skid plates, and winch-capable steel bumpers, this truck is trail-ready straight off the lot.
Its 6.6L Duramax Diesel engine, paired with the Allison 10-speed automatic transmission, delivers 470 horsepower and an astounding 975 lb-ft of torque. With towing capabilities exceeding 18,000 pounds and a payload rating of 2,600 pounds, this Sierra is ready to haul both gear and camper to the ends of the earth.
“For those looking to explore farther, stay off-grid longer, and do it all with unmatched comfort and confidence, the 2025 GMC Sierra 2500 HD AT4X AEV Edition stands at the pinnacle of heavy-duty overlanding right out of the box,” said Matt Feldermann, Overland Expo Ultimate Build Project Manager. “Everything we added only enhanced an already adventure-ready platform, making this our most epic Ultimate Build yet.”
The project began at American Expedition Vehicles (AEV) in Michigan, where additional enhancements took the truck from trail capable to expedition elite. Features of the truck include:
- AEV Salta XD Wheels paired with 37-inch BFGoodrich All-Terrain KO2 tires
- AEV 37-inch 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 offroad lights
- AEV Paint Appearance Package
- Magnaflow stainless steel exhaust for increased efficiency
- Air Lift LoadLifter 5000 Pro suspension kit for camper-readiness
The vehicle’s overlanding prowess is completed with the OEV Back Country 6.85 slide-in truck camper, offering four-season capability, an abundant amount of living space and storage, and a robust off-grid system including:
- 220 watt solar power system
- A 270 amp hour lithium battery
- Truma Combi heating/hot water system
- A Xantrex 2,000 watt inverter
- An Isotherm DC refrigerator-freezer
- Alu-Cab 270 awning
- A 20-gallon fresh water holding tank
- A Shower Cube
OEV’s Back Country is the ultimate slide-in truck camper. Its pop-up roof and spacious interior comfortably sleeps up to four people. The camper’s robust construction includes powder-coated aluminum extrusions, OEV’s Gen 4 Advanced Fiberglass Composite System (AFCS) walls with an R8 insulation value, and fire-rated four-layer soft walls (R4) for safety and comfort. The 1,345-pound camper offers a floor length of 6 feet 7 inches, is 6 feet 7 inches wide, and only 70 inches tall with the top down. The camper’s size and weight means that it is compatible with any full-size truck including half-ton, 3/4-ton, and one-ton trucks.
The final build phase took place at Tiny Rig Company in Southern California, known for its high-end craftsmanship. Its team wired auxiliary lighting, installed a Switch-Pros SP9000 system, and integrated a Midland CB radio for trail communications. Additional comfort and utility accessories include:
- 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
The Ultimate Build will debut at Overland Expo West, the premier overlanding event in the U.S., hosted in Flagstaff, Arizona, May 16–18, 2025. After touring the country—including stops at the remaining 2025 Overland Expo events and Outdoor Retailer—the Ultimate Build will be auctioned off, with all proceeds benefiting the Overland Expo Foundation. The foundation is dedicated to funding projects that support the overland community and the lands we’re lucky to explore.
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