Heavy Dump Truck


M917A3 Heavy DumpTruck

The Mack Defense M917A3 Heavy Dump Truck is a commercially-based Mack® Granite® dump truck, engineered to be the best-in-class tactical vehicle solution from the only company that can deliver these unparalleled capabilities to the U.S. Army. Mack Defense assembled a world class team with one purpose in mind — to provide the U.S. Army with a best-in-class heavy dump truck that meets all military requirements.

Downloadable Specification Sheets (.pdf)

Downloadable Brochures (.pdf)

Prepared for anything. The HDT is designed to match the demands of the most severe conditions.


Saving up to 2.5% in fuel and shedding 88 lbs in weight, Mack’s workhorse MP®8 engine offers up to 520 HP and 1,860 lb-ft of torque and the Euro 3 version is also available at 520hp and 1,844 lb-ft of torque.

6×6 or 8×8 Axle and Suspension Configurations

The Meritor® axles coupled with the Mack front parabolic spring and the Hendrickson rear Primaxx® suspension provides unparalleled ride quality with a fully loaded or empty payload.

Standard Cab or Optional Armor Cab

The cab design and driver environment are built around the way the work gets done – keeping drivers comfortable, safe, and focused all day long.

Specifications Overview
  • Up to 27 ton payload capacity
  • Up to 18 cubic yard dump
  • Diesel engine compatible with JP8
  • 2 person cab
  • Air lift ability
AWD Components
  • Front drive
  • Transfer case
  • High ground clearance air ride suspension
  • Tandem or tridem rear axle

The Cornerstone Chassis

This truck chassis off road superiority gives it the flexibility to transform into multiple mission capable platforms with proven success. The adaptability provides the military a diverse portfolio of tactical and logistical support equipment. The chassis is built strong (rock-solid) and when combined with a crane can offer an all-terrain solution capable of 30 to 60 tons. Making it the perfect tool for light, medium, and heavy lifts.


Mack has plenty riding on our Cornerstone chassis. Components were tested for fatigue; the rails and crossmembers were stressed and relentlessly checked for endurance.


The best All Wheel Drive truck maneuverability ever from Mack. The Cornerstone chassis design allows increased wheel cuts for improved handling around the job site.


The 300 mm constant frame rail height and high strength steel alloy in conjunction with a full length channel liner provide for optimal strength and payload capabilities. The frame system includes a full channel liner in each rail that runs front to rear within the Mack Defense M917A3 Heavy Dump Truck. This provides for optimal strength and payload capabilities.


Developed by Mack design engineers and harshly tested by perfomance engineers – superior strength and stiffness is achieve through the use of eight crossmembers located along the frame rails where loads are imposed


New engine mounts and cab isolators reduce noise and vibration — decreasing driver fatigue and improving productivity.


Offers military users the capability of transporting supplies on logistic and tactical missions.


Constructed with purpose. Prepared for anything.


High strength steel, Up to 18 cubic yards, Heated dump body


Mounted vertically between back of cab and dump body


Standard Swing Gate, Optional Material Control System (MCS), Optional shoots for specific materials


Collision Warning System, Military Lighting, NATO Slave Receptacle, 12/24V Electrical System, 12V SAE and 24V NATO Trailer Connections


Front bumper assembly – multipurpose HDT design with lifting eye and tie down feature and brush guard, Rear tie down/towing, Side lifting loop (Attached to frame)

Static Stability - Tilt Table

Mobility Testing

Speed, Stop and Start 30% Grade

16 and 20 Inch Vertical Step

Tested, tried, and true platform

The M917A3 HDT has passed its ruggedness challenge at the Nevada Automotive Testing Center. Passing these tests was especially important for the M917A3 and proved its design is ready to tackle the most rugged terrain. Clearly, the M917A3 has proven it has got the capability you need to take on tough jobs.

Test Result
Vertical Step
Step Static stability on tilt table
Wall-to-wall turning circle
Trench crossing
Speed on 0% grade
Speed, stop and start 30% grade
Steady state turning
Ride quality – half rounds
Side slope
Mobility Testing
Fording – 20 inches
Standard is -25oF to 120oF, can go to -40oF to 120oF with addition of cold weather kit

Meritor Protec Series 50 Rigid Tridem Axle

  • Gross axle weight rating (GAWR) of 30,000 lbs per axle
  • 3.46:1 Planetary geared wheel-end
  • Standard Driver-Controlled Differential Lock (DCDL) or automatic locking options
  • Central Tire Inflation System – (CTIS) and ABS-ready
  • Air disc brake or drum brake options

Meritor MX-810 Front Drive Steer Axle

  • Gross axle weight rating (GAWR) of 23,000 lbs
  • Standard Driver-Controlled Differential Lock (DCDL) or automatic locking options
  • Meritor bevel gear wheel-end reduction axles exceed the demanding requirements of the current Family of Medium Tactical Vehicles (FMTV)
  • 35°–38° turn angle for excellent maneuverability
  • EX+ air disc brakes standard or optional drum brakes
  • ABS-ready wheel ends with installed tooth wheel and sensor

Meritor Permalube™ RPL Series Driveline

  • Permanently lubricated and sealed for life – reduced maintenance and operating costs
  • Extended U-joint life to handle difficult terrains
  • Triple lip seals provide protection against contaminants
  • Nylon thrust washers eliminate metal-to-metal contact to prevent wear
  • Four-bolt design for easy installation and service
  • E-coated steel guard secures and protects the slip seal against contaminants and damage

Meritor MTC-3220FV (TC-142) Transfer Case

  • Speed – 3,000 RPM
  • High Input Torque – 20,000 lb-ft
  • Ratios – 1:1 and 2.23:1
  • Combined splash and pressurized lubrication system
  • Optional Full Power PTO, Integral Air Range Shift
  • High-torque helical high range gears with tapered roller bearings

Dump Body

  • 17′ Long Crysteel Select Dump Body
  • 18-22 yard capacity
  • Front Material 3/16″ AR450
  • Side Material 3/16″ AR450
  • Tailgate Material 3/16” AR450
  • Floor Material ¼” AR450
  • Heated Tubular Longsills and side rubrails
  • Std or Material Control System Tailgate Option
  • 50″ Cab protector
  • 12″ rear spill shield portable ladder access steps outside and inside, left front corner tire chain storage boxes, both sides asphalt tarp

Dump Body Cylinder

Chrome plated T74167 7″ barrel, 4 stages, 167″ stroke to achieve 50 degree dump angle

Includes Control Module with touch screen display to:

  • Operate dump body hoist
  • Operate the tarp and tailgate latch
  • Operate the body heater system
  • Operate the MCS doors
  • Inclinometer to show side slope and grade
  • Automatic shut down of the hoist if over 7% side slope or 15% uphill grade
  • On Board weigh scale

Armor Scalable Solutions.

Whatever the mission, this unique armored body system is designed to withstand the most challenging conditions.


  • GVW: 94,500 lbs
  • Wheel Configuration: 8×8
  • Frame: 300mm X 90mm X 11.1mm with steel reinforcement frame
  • Wheelbase: 243″
  • Platform: 230″
  • Overhang: 75″


  • Type: Mack 13 Liter, MP8 440
  • Max Power: 440 HP
  • Max Torque: 1660 lb-ft
  • Engine Brake: Engine brake, plus exhaust pressure governor (for HE/Export)
  • Fan Drive: Electronic modulating viscous fan drive
  • Air System: Meritor®/Wabco 636 (37.4 cfm) w/o clutch
  • Starter: 24 Volt
  • Alternator: High output, 24V alternator


  • Driveline: Meritor® Permalube RPL
  • Transmission: Allison® 4500 Gen5 with prognostics, 6-speed
  • Brakes: Meritor® EX+ air disc brakes front, Meritor Drum 16.5”x7” Q+ rear
  • ABS System: 6S/6M system
  • Front/rear Tires: 445/65R22.5 L Michelin® XZY3
  • Transfer Case: Fabco TC142


  • Front Axle: Meritor® MX-810
  • Front Suspension: Taperleaf spring suspension (parabolic), axle-forward position
  • Rear Axle: P600/ProTec Series 50, 76,800 lb Meritor® 34836
  • Carrier Ratio: 6.14
  • Rear Suspension: Primaxx® Pax 792 high stability 76,800 lb


  • Driver Seat (non-armored): Mack-air, high back, 1 chamber air lumbar
  • Passenger Seat (non-armored): Mack-air, high back, 1 chamber air lumbar
  • Mirrors (both sides): Aero black, heated/motorized, wide angle, w/o lamps
  • Spare Tire: Spare tire/carrier between dump body and cab
  • Left Side Fuel Capacity: P93 gal (350 L), 26″ aluminum d-shape
  • Right Side Fuel Capacity: N/A