Last month the Department of Defense finally selected a worthy successor to the tried-and-true HMMWV (HUMVEE phonetically) that originally deployed in the 1980s. Called the Joint Light Tactical Vehicle (JLTV) and built by Wisconsin-based Oshkosh Defense, it combines many of the lessons from the past decade into a single vehicle built to fill multiple battlefield roles, from scout to armored weapons platform to military ambulance.

But while the JLTV is a combat vehicle built with future conflicts in mind, it will use a tried-and-true powerplant for motivation, the GM Duramax diesel, reports Automotive News. With as many as 55,000 JLTVs planned for purchase over the next decade, this is hardly GM’s largest defense contract ever, but it’s still a win for the die-hard Duramax.

There were plenty of other options to consider when choosing which engine to drive the JLTV, including the outgoing 6.5-liter Optimizer 6500 that powered the HMMWV. But Oshkosh ultimately opted for something a bit more updated, the introduced-in-2001 GM Duramax 6.6-liter turbo diesel. The Duramax has undergone several performance-enhancing improvements since its debut, but it still uses an overhead-valve setup with four-valves per cylinder.

In other words, it’s still a mostly-simple engine with a long track record of reliability. Oshkosh will make further improvements to the military-grade Duramax in a bid to boost both performance and fuel economy. The initial contract calls for just 17,000 vehicles, but could be extended for some 55,000 JLTVs for both the Army and Marines at a cost of $50 billion, or about $909,000 per vehicle.

Freedom ain’t free, right?