We all know that turbo-diesel pickup trucks are great at towing trailers (especially in the mountains), but is it worth buying a diesel truck if you are mainly using it as a commuter? This is why we are taking two new Chevy Silverado HD 2500 trucks on our Denver 100 MPG loop. One has a 6.6L gas V8 engine under the hood, the other has a 6.6L Duramax turbo-diesel V8 under the hood. Both of these trucks have a 10-speed Allison-branded automatic transmission. The diesel truck should be more efficient, but the diesel fuel is so much more expensive. Is the diesel truck still worth it? Let’s dig in and find out what happens!
These are the trucks we are testing.
- 2026 Chevy Silverado HD 2500 LTZ with a Z71 off-road package. This one has the gas V8.
- 2025 Chevy Silverado HD 2500 Z71 Trail Boss off-road package. This one has the diesel V8.
The 6.6L gas V8 is rated at 401 horsepower and 464 lb-ft of torque. It has a 3.73-to-1 rear axle ratio. The 6.6L diesel V8 is rated at 470 horsepower and 975 lb-ft of torque. It has a 3.42-to-1 rear axle ratio.
We are putting in 87-octane into the gas truck (although we have cheaper 85-octane fuel available in Colorado). This 87-octane was $4.18 per gallon at the time of this test in April 2026. The ultra-low sulfur diesel fuel costs $4.99 per gallon at the time of this test.
In the end, the gas truck registered 16.1 MPG and used 7.5 gallons for this 121 mile trip. The diesel truck returned 20.9 MPG and used 5.78 gallons for this identical trip. We paid $31.42 for the gasoline and $28.92 for the diesel. Indeed, the diesel was $2.50 cheaper to drive for this trip.
The 6.6L Duramax V8 was a $9,500 option in 2025. If you are saving $2.50 for this trip, it would take approximately 460,000 miles to payback the $9,500 difference for the diesel engine.
The answer is, the turbo-diesel is worth buying if you are driving a lot of miles and if you are towing heavy trailers. We are doing a Gas vs Diesel towing Denver 100 MPG loop very soon.
