The GMC Sierra 1500 AT4 3.0 Duramax Turbo-Diesel, introduced with the GMTT1XX facelift in 2022, represents a significant offering in the full-size pickup truck segment. This variant combines the capability expected of a Sierra 1500 with the efficiency and torque characteristics of a modern diesel engine. Positioned as a mid-to-upper trim level, the AT4 focuses on off-road capability and a more rugged aesthetic while still providing the comfort and technology features demanded by North American truck buyers. Production for this specific configuration was limited to the 2022 model year.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 V (GMTT1XX, facelift 2022) Crew Cab Short Box |
| Type (Engine) | AT4 3.0 Duramax TD (277 Hp) 4WD Automatic |
| Start of production | 2022 |
| End of production | 2022 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 11.2 l/100 km (21 US mpg) |
| Fuel consumption (extra urban) | 10.2 l/100 km (23.1 US mpg) |
| Fuel Type | Diesel |
| Weight-to-power ratio | 9.1 kg/Hp |
| Weight-to-torque ratio | 4 kg/Nm |
| Power | 277 Hp @ 3750 rpm |
| Power per litre | 92.3 Hp/l |
| Torque | 623 Nm @ 1500 rpm (459.5 lb.-ft. @ 1500 rpm) |
| Maximum engine speed | 5100 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | LM2 |
| Engine displacement | 3000 cm3 (183.07 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 15:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 6.6 l (6.97 US qt | 5.81 UK qt) |
| Coolant capacity | 20.7 l (21.87 US qt | 18.21 UK qt) |
| Kerb Weight | 2508 kg (5529.19 lbs.) |
| Max. weight | 3175 kg (6999.68 lbs.) |
| Max load | 667 kg (1470.48 lbs.) |
| Fuel tank capacity | 83.3 l (22.01 US gal | 18.32 UK gal) |
| AdBlue tank capacity | 20.5 l (5.42 US gal | 4.51 UK gal) |
| Permitted trailer load with brakes (12%) | 3992 kg (8800.85 lbs.) |
| Length | 5916 mm (232.91 in.) |
| Width | 2063 mm (81.22 in.) |
| Width including mirrors | 2478 mm (97.56 in.) |
| Height | 1990 mm (78.35 in.) |
| Wheelbase | 3747 mm (147.52 in.) |
| Ride height (ground clearance) | 276 mm (10.87 in.) |
| Approach angle | 25.5° |
| Departure angle | 23.0° |
| Ramp-over (brakeover) angle | 20.9° |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| Number of gears and type of gearbox | 10 gears, automatic transmission |
| Front suspension | Independent coil spring |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 330×30 mm |
| Rear brakes | Ventilated discs, 345×20 mm |
| Steering type | Steering rack and pinion |
| Power steering | Electric |
| Tires size | 265/65 R18 |
| Wheel rims size | 8.5J x 18 |
Introduction
The 2022 GMC Sierra 1500 AT4 with the 3.0L Duramax Turbo-Diesel engine and 10-speed automatic transmission represents GMC’s attempt to bridge the gap between traditional full-size truck capability and the growing demand for improved fuel efficiency. Built on the GMTT1XX platform, which debuted with the 2019 Sierra 1500, the 2022 facelift brought updated styling and enhanced technology. The AT4 trim, introduced in 2019, specifically targets buyers seeking a more off-road oriented vehicle without sacrificing on-road comfort. This diesel variant offered a compelling alternative to the gasoline-powered engines available in the Sierra 1500 lineup.
Powertrain & Engine Architecture
The heart of this Sierra 1500 AT4 is the GM LM2 3.0-liter inline-six cylinder turbo-diesel engine. This engine utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. The engine features a single variable geometry turbocharger (VGT) and an intercooler to increase air density and boost power output. The valvetrain employs a Double Overhead Camshaft (DOHC) design with four valves per cylinder, contributing to efficient engine breathing. The LM2 engine is known for its robust construction and relatively quiet operation for a diesel.
The engine is paired with a 10-speed automatic transmission (specifically the 10L80) designed to maximize efficiency and provide smooth shifting. This transmission features a wide gear ratio spread, allowing the engine to operate in its optimal power band more frequently. The transmission is electronically controlled and adapts to driving conditions and driver input. The 4WD system is an electronically controlled, on-demand system, allowing the driver to select between 2WD, 4WD Auto, 4WD High, and 4WD Low.
Driving Characteristics
The 277 horsepower and 623 lb-ft of torque produced by the LM2 engine provide ample power for everyday driving and towing. While not as quick off the line as the larger gasoline engines, the diesel offers a broad torque curve, making it exceptionally capable for hauling and towing. The 10-speed automatic transmission helps to keep the engine in its sweet spot, delivering smooth and responsive acceleration. The gear ratios are tuned for both fuel efficiency and towing performance. In real-world conditions, the AT4 diesel provides a comfortable and capable driving experience, particularly noticeable when carrying a load or navigating challenging terrain. Compared to the 5.3L or 6.2L V8 options, the diesel prioritizes torque and fuel economy over outright acceleration.
Equipment & Trim Levels
The AT4 trim level comes standard with a number of features designed to enhance both off-road capability and interior comfort. Standard equipment includes a leather-appointed interior with unique AT4 badging, heated and ventilated front seats, an 8-inch touchscreen infotainment system with Apple CarPlay and Android Auto compatibility, and a premium audio system. Available options included a larger 12.3-inch digital instrument cluster, a head-up display, adaptive cruise control, and a multi-function tailgate. Exterior features specific to the AT4 included a unique grille design, black chrome accents, and off-road tuned suspension.
Chassis & Braking
The Sierra 1500 AT4 utilizes a fully boxed frame for enhanced rigidity and durability. The front suspension features independent coil springs, while the rear suspension employs a traditional leaf spring setup. The AT4 trim includes Rancho shocks tuned for off-road performance. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. The AT4 also includes an electronic stability control system with trailer sway control and hill start assist.
Market Reception & Comparison
The GMC Sierra 1500 AT4 3.0L Duramax Diesel received generally positive reviews from automotive critics. It was praised for its combination of capability, fuel efficiency, and comfortable ride. Compared to the gasoline-powered Sierra 1500 models, the diesel offered significantly better fuel economy, particularly during highway driving. However, the diesel engine carried a higher price tag. Compared to other diesel-powered full-size trucks, such as the Ram 1500 EcoDiesel, the Sierra 1500 offered a competitive level of performance and features.
Legacy
The LM2 3.0L Duramax engine has proven to be a reliable and durable powerplant. While the 2022 model year was a short run for this specific configuration, the engine itself has continued in production for other GM vehicles. The Sierra 1500 AT4 3.0L Duramax Diesel remains a desirable option on the used car market, particularly for buyers seeking a capable and fuel-efficient full-size truck. Its combination of off-road capability, comfortable interior, and modern technology continues to appeal to a wide range of truck buyers.
