MUSKEGON, Mich., June 27, 2026 — The U.S. Army Contracting Command at Detroit Arsenal has awarded RENK America a new five-year indefinite-delivery/indefinite-quantity (IDIQ) production contract to continue manufacturing and sustaining the HMPT 800 hydromechanical transmission for the Army's medium tracked vehicle fleet.
Announced on June 26, the contract has a potential value of up to $691 million and marks the fourth consecutive multi-year award for the HMPT 800 program. The latest agreement continues a long-running partnership established under the Army's Transmission Heavy Off-Road (THOR) program, which serves as the contracting framework for medium tracked vehicle drivetrains.
Since the beginning of the THOR program, RENK America has delivered more than 4,500 HMPT transmissions to support several U.S. Army combat vehicle programs. The repeated contract awards reflect the continued use of the HMPT transmission family across the Army's medium tracked vehicle fleet, where there is currently no domestically produced transmission in the same weight and performance class.
HMPT 800 Supports Key Armored Vehicles
The HMPT 800 is the primary drivetrain transmission for tracked combat vehicles weighing up to 45 metric tons (99,000 pounds) and is designed to operate with engines producing up to 800 horsepower. The transmission converts engine power into controlled movement, allowing armored vehicles to operate efficiently on roads and across difficult off-road terrain.
The transmission is installed in several major U.S. Army platforms, including the Armored Multi-Purpose Vehicle (AMPV), the Bradley Fighting Vehicle, the Multiple Launch Rocket System (MLRS), and the M109A7 Paladin Self-Propelled Howitzer.
AMPV Program Drives Current Production
The AMPV represents the largest ongoing application of the HMPT 800. Developed by BAE Systems on a Bradley-derived chassis, the vehicle entered full-rate production in 2023 as the Army's replacement for the aging M113 armored personnel carrier.
The vehicle is powered by a Cummins VTA903E-T675 diesel engine generating 504 kilowatts (676 horsepower), paired with the HMPT 800 transmission. This drivetrain enables the approximately 36-ton vehicle to reach a maximum road speed of 61 km/h (38 mph) while providing an operational range of approximately 362 kilometers (225 miles).
The AMPV family currently consists of five baseline variants: troop transport, medical evacuation, medical treatment, mission command, and mortar carrier. Additional configurations featuring counter-drone systems, remotely operated 30 mm cannons, and autonomous driving technologies have also been introduced. Every variant uses the same HMPT 800 transmission, making the Muskegon production facility an important part of the vehicle's supply chain.
Evolution of the HMPT Transmission Family
The HMPT transmission family has supported U.S. Army armored vehicles for more than four decades. Earlier Bradley Fighting Vehicles were equipped with the HMPT-500, with production exceeding 11,000 units for U.S. and international customers.
The HMPT 800 was developed as a higher-capacity successor capable of supporting heavier vehicles and more powerful engines while maintaining compatible external interfaces. This design approach allows integration into newer vehicle platforms without requiring extensive modifications to existing drivetrain layouts.
Supporting Current and Future Army Programs
The contract supports continued operation of the Army's existing armored vehicle fleet while next-generation combat vehicles remain under development. The XM-30 Mechanized Infantry Combat Vehicle, planned as the replacement for the Bradley Fighting Vehicle, received Milestone B approval in June 2025, with prototype deliveries expected later in fiscal year 2026. Operational fielding is expected to take several more years, leaving the Bradley and AMPV as the Army's primary medium tracked combat platforms during the transition period.
To support future vehicle requirements, RENK America is also developing Project Wolverine, an upgraded transmission designed for vehicles weighing up to 50 metric tons and engines producing 1,000 horsepower. The upgraded system is being designed to retain the same physical dimensions as the HMPT 800, allowing future integration without major vehicle redesign.
The new five-year contract ensures continued production and sustainment of the HMPT 800 transmission, supporting the operational readiness of the U.S. Army's current fleet of medium tracked armored vehicles while modernization programs progress toward fielding.
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