Is the 2025 Chevy Silverado HD Duramax the Most Efficient Diesel HD Truck on the Denver 100 MPG Loop?

Will the Chevy Silverado HD Trail Boss beat the Ford Super Duty and Ram Cummins in the MPG race?

HD diesel trucks are torque monsters, but just how fuel efficient is our Chevy Silverado 2500HD Trail Boss?

Over the years, we’ve worked to bring you a range of real-world truck testing. From the Ike Gauntlet to off-road testing and various fuel economy loops, the goal is to give you as much usable information as we can covering the latest midsize, full-size and heavy-duty trucks on the market. And in that vein, Andre and Kase are running our new 2025 Chevrolet Silverado 2500HD Trail Boss on the Denver 100 MPG loop. Unlike the other truck segments, the EPA does not rate HD truck models, so we wanted to know whether this truck is the most efficient option — at least among similar offerings from Ford and Ram — for your money.

For precedent, we have extensive tests to lean back on with our off-road-built Ram 2500 “Trailhound” series. We’ve also tested the latest generation Ford F-250 Super Duty with Ford’s 6.7-liter Power Stroke engine, putting out 500 horsepower and 1,200 lb-ft of torque. Our previous Ram 2500’s standard output 6.7-liter Cummins put out 370 horsepower and 850 lb-ft of torque. With its 2025 updates, though, all Ram HD models get the “High Output” engine as the only diesel option, with 430 horsepower and 1,075 lb-ft on tap.

Here’s where the Duramax stacks up against the competition right now:

2025 Cummins H.O.2025 Power Stroke H.O.2025 GM Duramax
Engine6.7L I66.7L V86.6L V8
Power430 hp500 hp470 hp
Torque1,075 lb-ft1,200 lb-ft975 lb-ft

Ford and GM both use 10-speed automatic transmission, while our earlier Ram uses a 6-speed (though again, 2025s now get a new TorqueFlite 8-speed automatic across the board).

In Andre’s previous testing, the Ford F-250 Tremor Power Stroke managed 19.6 MPG in our 111-mile test at highway speeds between 65-75 miles per hour. The Ram 2500 “Trailhound” truck, by comparison, achieved 17.9 MPG, which was about 1 MPG off from what the trip computer suggested our lifted truck on beefy all-terrain tires could do. That said, the new Ram HD may well manage a figure very similar to the Ford Super Duty, and we’ll be testing that out in the coming weeks.

We’ve also tested a dually Chevy Silverado 3500 with the Duramax turbo-diesel, where it managed 17.7 MPG. But what about the Trail Boss? Well, using the same loop and methodology as the other tests, this HD truck used 5.486 gallons of fuel. That works out to a pretty remarkable 20.4 MPG, which indeed does make it the most fuel efficient diesel heavy-duty we’ve tested on the Denver 100 loop so far!