2027 GMC Sierra AT4 Offers Duramax Diesel at No Extra Cost

$73,495 is the key number in GMC’s newly populated 2027 Sierra 1500 configurator. That is the listed starting price of a four-wheel-drive AT4 Crew Cab Short Bed with either its standard 5.7-liter V8 or the optional 3.0-liter Duramax turbodiesel. On this trim, changing from gasoline to diesel adds nothing to the initial price.

The figures were recorded from GMC’s Build & Price tool on October 29, 2026, using a New Hampshire ZIP code. Each price includes a $2,795 destination charge but excludes taxes, title charges, dealer fees and other options. Dealers set final prices.

The AT4’s no-cost diesel substitution stands out because GMC does not apply one uniform Duramax premium across the Sierra range. Relative to the 5.7-liter V8, the diesel costs $345 more on the Pro, $50 less on the Elevation, nothing more on the AT4 and $495 more on the Denali. It is the standard engine on the AT4X and Denali Ultimate.

Engine prices change with the trim

For a four-wheel-drive Pro Crew Cab Short Bed, the configurator lists the TurboMax gasoline engine at $51,295, the 5.7-liter V8 at $53,985 and the Duramax at $54,330. The diesel therefore costs more than either gasoline option on this entry trim, including $3,035 more than the TurboMax.

The four-wheel-drive Elevation Crew Cab Short Bed starts at $59,995 with the TurboMax. Moving to the Duramax raises the price to $62,635, while the 5.7-liter V8 produces a slightly higher $62,685 total. Here, the diesel is $2,640 above the TurboMax but $50 below the V8.

GMC’s packaging changes again on the AT4. Its standard 5.7-liter V8 and available Duramax both produce the same $73,495 starting figure. The AT4 is four-wheel-drive only, so there is no less expensive two-wheel-drive version against which to compare the engine choice.

A four-wheel-drive Denali Crew Cab Short Bed starts at $76,795 with the standard 5.7-liter V8. The Duramax raises that figure to $77,290, a $495 increase. The available 6.6-liter V8 takes the Denali to $80,090, or $3,295 above the standard V8.

The two highest trims reverse the usual option structure by making the Duramax standard. The AT4X is listed at $85,495 with the diesel and $88,000 with the 6.6-liter V8. The Denali Ultimate starts at $86,480 with the Duramax, while selecting the 6.6-liter V8 increases the price to $87,895 a $1,415 difference.

Some configurations narrow the engine menu

The 6.6-liter V8 appears only on three four-wheel-drive trims in the configurator: Denali, AT4X and Denali Ultimate. Its acquisition cost is not the only distinction. GMC’s 2027 documentation recommends 91-octane premium gasoline for the 6.6-liter engine, although 87 octane may be used with reduced performance and driveability. The 5.7-liter V8 and TurboMax are specified for regular 87-octane gasoline, while the Duramax requires diesel fuel.

At the other end of the range, the 5.7-liter V8 costs $2,690 more than the TurboMax on both Pro and Elevation models, regardless of whether the truck has two or four-wheel drive. GMC marks the TurboMax as late availability on those trims, adding a timing constraint to the lowest-priced engine choice.

Drivetrain selection creates another substantial price step. Four-wheel drive adds $3,300 to a Pro Crew Cab, $4,000 to an Elevation and $3,100 to a Denali. The AT4, AT4X and Denali Ultimate are restricted to four-wheel drive.

The configurator also lists the 2027 Regular Cab for the first time, but only in Pro trim with the TurboMax engine. A two-wheel-drive Regular Cab Standard Bed starts at $42,095, and the corresponding four-wheel-drive truck starts at $46,695. The Double Cab, although identified alongside the Regular Cab as late availability in the cited order information, was not present in the configurator when prices were checked.

GMC’s engine pricing is therefore tied closely to trim and drivetrain packaging rather than a fixed powertrain surcharge. The clearest example remains the AT4: its $73,495 price does not change when the standard V8 is replaced by the Duramax, even though the same diesel carries a premium on the Pro and Denali and a small discount on the Elevation.

By Thomas Caldwell — AMI’s senior editor for mechanical and mobility engineering, covering vehicle electronics, systems integration, electrification, chassis systems, propulsion, and safety policy.