Built for the future: Mack Defense expands military mission

From battle-tested reliability to next-gen innovation, Mack Defense is delivering on its promise to support the U.S. military with vehicles that go beyond expectations. Building on decades of trusted service — and the legendary Bulldog spirit — Mack Defense is entering a new chapter of growth and momentum.

With the recent award of a new five-year contract for its proven M917A3 Heavy Dump Truck (HDT), involvement in the U.S. Army’s Common Tactical Truck (CTT) program, and a U.S. Marine Corps development contract for the future Medium Tactical Truck (MTT), Mack Defense is rapidly expanding its role across military branches.

This is more than a story of trucks — it’s about trust earned through performance, innovation driven by mission needs, and the commitment to serve wherever and whenever duty calls.

Mission-ready performance: The M917A3 HDT

The backbone of this continued trust is the proven M917A3 HDT—a truck based on the durable and versatile Mack® Granite® platform. The HDT has been praised for its performance in some of the toughest environments on Earth, from overseas combat zones to domestic emergency response.

“The M917A3 is a commercial-based truck, ruggedized to meet the toughest military demands, said David Hartzell, president of Mack Defense. “It’s a testament to our team’s skill and to the robust capabilities of the Mack platform.”

Each truck is built with enhanced suspension, heavier-duty rear axles, increased ride height, and all-wheel drive. Additional upgrades include ABS, modern control interfaces, active safety systems, and durable coatings—all of which allow the truck to operate in extreme conditions. In addition, the truck’s high ground clearance, rugged mobility, and hauling capacity prove invaluable for transporting materials and clearing debris in difficult-to-navigate areas and disaster zones.

In 2021, Mack Defense began full-scale HDT production at its dedicated assembly line at the Mack Experience Center in Allentown, Pennsylvania, following a $6.5 million facility investment. Since then, every vehicle has undergone rigorous quality inspections conducted by military auditors. With precision manufacturing and a highly specialized workforce, Mack Defense ensures each HDT exceeds operational requirements.

“These vehicles play a vital role in supporting construction and infrastructure, including airfields, roadways, motor pools, and landing strips,” Hartzell said. “We’ve worked hard to design, build, and deliver a truck that performs where it counts.”

Celebrating 500th truck milestone

In March 2025, Mack Defense celebrated the delivery of its 500th M917A3 Heavy Dump Truck, part of the original $296 million, seven-year contract awarded in 2018. The U.S. military has now ordered 549 trucks under that contract, with 74 funded through the 2024 presidential budget and 29 ordered by the U.S. National Guard.

“We’re excited that we’ve produced 500 of the Mack HDTs to date, fulfilling the operational needs of our military,” said Hartzell. “We want to thank our Mack Defense employees who made this possible.”

New M917A3 HDT contract

Mack Defense is forging ahead in its mission to support the U.S. military with dependable, mission-ready trucks. In a major milestone, the company has secured a new five-year contract worth up to $221.8 million to deliver as many as 450 additional M917A3 Heavy Dump Trucks to the U.S. Army. The award builds on the trust earned through years of consistent delivery and performance. The Army has also placed the first order of 86 HDT’s against the new contract.

“This contract represents continued confidence in our ability to deliver mission-critical vehicles,” said Hartzell.

Success drives expansion

The HDT’s battlefield and domestic performance record paved the way for deeper involvement across the armed forces.

Since World War I, Mack trucks have been synonymous with strength and reliability. In 1916, Mack built its first armored vehicle for the New York State National Guard. By 1918, British troops were calling the trucks “Bulldogs” for their grit and resilience on the battlefield — a name that stuck.

Mack trucks helped support Eisenhower’s historic 1919 cross-country military convoy and earned the Army-Navy “E” Award in World War II for wartime production. From the jungles of Vietnam to the deserts of Iraq and Afghanistan, Mack’s military presence has never wavered.

Mack Defense was formally established in 2011 as a dedicated, fully functional wholly-owned subsidiary of Mack Trucks to serve military and government customers. Since then, it has led programs for the Canadian Army, partnered on mine-resistant vehicles, and continued to expand its capabilities globally.

In 2023, the U.S. Army selected Mack Defense for the prototype and testing phase of the Common Tactical Truck (CTT) program — designed to replace the Army’s fleet of 35,000 heavy tactical trucks with a new, standardized platform. In 2024, Mack Defense delivered its CTT prototypes to the Army’s Aberdeen Proving Grounds which then underwent rigorous vehicle performance and durability testing. Once our vehicles successfully passed the testing phase the Army conducted full soldier evaluations of the prototype vehicles all aimed at developing the final requirements for the future CTT vehicles. Mack Defense’s prototypes once again leveraged the Mack commercial Granite platform but included many enhancements to meet the strict demands of the Army’s heavy tactical logistics fleet including advanced technologies to meet future operational needs such as autonomous system integration capability and hybrid electric systems to reduce fuel consumption and provide exportable power. Mack Defense is currently preparing for the upcoming competitive production contract phase of the program.

In 2025, Mack Defense's role expanded further when the U.S. Marine Corps awarded the company a 12-month contract to begin development of the next-generation Medium Tactical Truck (MTT) fleet. The MTT program will replace the Marines' Medium Tactical Vehicle Replacement (MTVR) family, which includes cargo, dump, wrecker, tractor, and re-supply trucks supporting combat support missions.

The Marine Corps' early requirements for the MTT focus on three hybrid-electric cargo variants with 10-, 15-, and 20-foot bed configurations. These trucks will feature silent watch capabilities, enhanced fuel efficiency, a 70% off-road and 30% on-road profile, and 60-inch fording capability. Onboard and external power systems —10-kilowatt and 30-kilowatt, respectively—will support advanced field operations, while military-grade safety and protection systems are designed to protect personnel in challenging environments. “We were confident in our ability to meet the needs outlined by the U.S. Marine Corps,” said Hartzell. “Being chosen for the initial development phase confirms that the Marine Corps recognizes Mack Defense’s proven expertise in designing tactical vehicle platforms that meet the most demanding requirements.”

Mack Defense will deliver an open-systems architecture engineering package for all three variants, enabling easy integration of future technologies. The designs are focused on achieving significant fuel savings and delivering military-grade mobility and safety for Marines worldwide.

Built from the ground up

“When any of our military trucks are on display, customers walk right past the commercial models to view them,” Hartzell noted. “It’s just so rewarding to see the impact the trucks make, whether in a convoy or at a show.” He adds that the impact of seeing Mack trucks in full camo, rolling down U.S. highways in a convoy is good for Mack and for the U.S. Military. That pride in performance runs through every aspect of Mack Defense’s operation. From engineering to production, from supplier collaboration to delivery, Mack Defense oversees every component of the process. Unique military requirements—whether classified armor specs, hybrid technologies, or enhanced safety—are addressed and integrated at every step.

“We are all proud of being part of Mack Trucks,” said Hartzell. “I’ve been with the company since 1988, and I like to say that Bulldog blood runs in my veins. As Mack takes on a larger role in the U.S. Military, we take pride in knowing our trucks will meet the mission.”

The road ahead

With the new HDT contract secured, CTT testing underway, and MTT development moving forward, Mack Defense is delivering more than just vehicles — it’s delivering confidence, capability, and continuity for U.S. military operations around the world.

“From day one, we’ve worked hard to foster a transparent, collaborative relationship—one that has helped ensure these programs remain on track, on time, and aligned with the Army and Marine Corps’ evolving needs,” said Derik Beck, senior director of sales, marketing and business development at Mack Defense. “This program is not only vital to readiness, but also to preserving critical manufacturing jobs and capabilities within our U.S. industrial base.”

Whether it’s building runways, recovering from a hurricane, or powering forward into tomorrow’s hybrid-electric fleet, Mack Defense continues to do what it has always done—answer the call.

The M917A3 HDT is not just a battlefield asset. When Hurricane Helene struck North Carolina, the U.S. National Guard relied on Mack HDTs for disaster recovery operations. Whether deployed overseas in conflict zones or at home in response to natural disasters, Mack Defense trucks are engineered to deliver critical support when and where it’s needed most.

Since World War I, Mack trucks have been synonymous with strength and reliability. In 1916, Mack built its first armored vehicle for the New York State National Guard. By 1918, British troops were calling the trucks “Bulldogs” for their grit and resilience on the battlefield—a name that stuck.