GM remains the last American truckmaker selling a diesel engine in mainstream light-duty pickups, a distinction Ford and Ram abandoned years ago. The 2026 GMC Sierra 1500 Denali Ultimate pairs that turbocharged diesel inline-six with luxury appointments, creating a truck suited to both work and highway comfort.
The 2992-cc turbodiesel inline-six delivers 0–60 mph in 6.8 seconds and generates more torque than GM's 6.2-liter gasoline engine despite smaller displacement. It produces its full torque at 2750 rpm and reaches 94 percent of maximum twist by 1500 rpm, providing immediate low-end power useful for passing and towing. The motor runs quieter than typical diesel engines, fitting the Denali's luxury positioning.
EPA ratings show 22/26/24 mpg city/highway/combined. A test drive achieved 28.7 mpg on a long highway stretch at speeds above 70 mph. The truck's 500-plus-mile highway range per tank pairs well with Super Cruise hands-free driving assistance and heated, ventilated front seats with massage functions.
The Denali Ultimate trim starts at $87,195 and tested at $89,204. It adds power-folding steps, 22-inch chrome wheels, and full-grain Alpine Umber leather with open-pore wood trim compared to the base Denali, a roughly $5,000 premium. The 2027 model year switches to an all-black interior with expanded screens, replacing the current Western-inspired design.
Diesel fuel costs present a real-world concern. At $6.50 per gallon average, fill-ups run approximately $130. The Ram 1500 Tungsten competes directly at the luxury truck tier, though Chevrolet Silverado High Country, Ford F-150 Platinum, and Toyota Tundra Capstone models also target buyers seeking upscale cabins.