Who doesn’t love a dump truck? And what’s even cooler than a typical dump truck? How about an armored military dump truck. The folks at Mack Defense just announced that the U.S. Federal government has ordered an additional 103 Mack Defense M917A3 Heavy Dump Trucks (HDTs) as part of a contract awarded by the Army in 2018. The contract, valued at $296 million, allows for the purchase of up to 683 dump trucks.

Our military continues to field Mack HDTs into various operations around the
world, so these vehicles have been put to the test and continue to meet demanding
requirements -Dave Hartzell, president of Mack Defense 

The Army, Army Reserve and the Army National Guard continue to invest in these modern HDTs to ensure our soldiers have the right truck with the highest level of capabilities needed to ensure mission success.

The Mack Defense M917A3 HDT is based on the company’s commercially available Granite model. However, these trucks come spec’d with heavier-duty rear axles, standard all-wheel drive, an increased ride height, and many other ruggedized features necessary to meet the unique requirements of the U.S. military.

Powering the Mack Defense M917A3 HDT is the company’s 13.0-liter MP8 440 turbodiesel inline six-cylinder engine. In this application, the engine produces 440 hp and 1,660 lb-ft of torque. Options for up to 520 hp and 1,860 lb-ft of torque are available. In addition to diesel, this engine also comes tuned to run on JP8. The engine is backed by an Allison 4500 Gen5 six-speed automatic transmission and Meritor MTC-3220FV transfer case with a 2.23:1 low range.

Mack Defense offers several variations of the M917A3 HDT, including 6×6 and 8×8 applications. These trucks are capable of hauling up to 27 tons of payload in an 18 cubic yard dump bed. Heavy-duty Meritor axles are coupled with Mack front parabolic springs while the rear is supported by Hendrickson Primaxx severe duty air springs. The truck’s Meritor Protec Series 50 axles offer a gross axle weight rating (GAWR) of 30,000 pounds each, feature 3.46:1 planetary geared wheel ends, are central tire inflation system (CTIS) ready, offer automatic or electronic locking differentials, and can be fit with either disc or drum brakes.

To ensure that it’s ready for military service, the Mack M917A3 HDT has undergone rigorous testing at the Nevada Automotive Testing Center. These trials include the ability to traverse both a 16- and 20-inch vertical step; stop, start, and hold on a 30-degree slope; ford up to 20 inches of water; remain stable on a side-slope tilt-table; and operate effectively between -25 degrees and 120 degrees Fahrenheit, among others.

Production of the Mack M917A3 HDT began in the first quarter of 2021 following a $6.5-million-dollar investment to create a dedicated production line at the company’s Mack Experience Center (MEC) in Allentown, Pennsylvania.