2027 GMC Sierra 1500 AT4
By Lorenzo Bianchi September 23, 2026
The AT4 gets a new 5.7-liter V8 producing 402 hp and 428 lb-ft, paired with a 10-speed automatic.
A factory 2-inch lift, monotube shocks and 34-inch all-terrain tires are standard.
The 2027 Sierra 1500 AT4 4WD Crew Cab starts at $73,495 including destination charges.
The 2027 GMC Sierra 1500 AT4 arrives as part of a substantial update for GMC's full-size pickup, bringing revised styling, a redesigned cabin and a new standard V8 to the off-road-focused trim.
The AT4 sits between the more road-oriented Elevation and the harder-edged AT4X. For 2027, GMC describes it as the choice combining premium comfort with enhanced off-road capability.
More Upright Face Leads The Sierra Redesign
The wider Sierra range adopts a more upright exterior, centered around a taller vertical grille. GMC has also reworked its signature lighting with 7-shaped headlamps and taillamps, while welcome and farewell animations and illuminated GMC signature lighting are available.
AT4's stance is backed up by functional hardware rather than appearance changes alone. A 2-inch factory-installed lift, monotube shocks and 34-inch all-terrain tires are standard. GMC also lists enhanced off-road content for the trim, while 20-inch wheels are available.
The MultiPro Tailgate has been revised too, gaining a new applique, four extra tie-downs and an integrated ruler. The bed provides 16 standard tie-down locations.
Redesigned Cabin Gets A 16.3 Inch Screen
Inside, the AT4 receives 12-way power-adjustable heated and ventilated front seats, a panoramic sunroof and Head-Up Display. Its 12.2-inch Driver Information Center sits alongside a 16.3-inch central infotainment touchscreen. An eight-speaker Bose Premium Audio system with a Richbass woofer is standard.
The new MultiPro center console adds storage and an extended work surface. Dual MagSafe wireless charging and dynamic ambient lighting are also included on AT4. An available Technology Package adds an 11.5-inch passenger display with an articulating cover and underbody cameras.
New 5.7 Liter V8 Makes 402 HP
The major mechanical change is GMC's sixth-generation 5.7-liter Small Block V8. It produces 402 hp and 428 lb-ft of torque and is standard on AT4, paired with the 10-speed automatic used across the 2027 Sierra engine range.
The 3.0-liter Duramax turbo-diesel remains available, producing 305 hp and 495 lb-ft. GMC also offers an approximately 34-gallon fuel tank.
Super Cruise with trailering capability is now standard on AT4, adding a notable road-trip feature to a trim primarily distinguished by its off-road hardware.
The 2027 Sierra 1500 AT4 starts at $73,495 for a 4WD Crew Cab, including the $2,795 destination freight charge. AT4X moves the formula further toward serious trail use with 35-inch mud-terrain tires, electronic locking differentials and Multimatic hardware, leaving AT4 as the less specialized of GMC's two dedicated off-road Sierra trims.