The GMC Sierra 2500HD, particularly the variant introduced with the GMTT1XX facelift in 2024, represents GMC’s entry into the heavy-duty pickup truck segment. This specific configuration – a Double Cab with a Standard Bed, powered by the 6.6-liter V8 engine producing 401 horsepower and paired with a 10-speed automatic transmission and four-wheel drive – occupies a significant position within the Sierra 2500HD lineup, balancing capability with everyday usability. It caters to buyers needing substantial towing and hauling capacity without the added length or complexity of higher trim levels.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD V (GMTT1XX, facelift 2024) Double Cab Standard Bed |
| Type (Engine) | 6.6 V8 (401 Hp) 4WD Automatic |
| Start of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.8 kg/Hp, 127.6 Hp/tonne |
| Weight-to-torque ratio | 5 kg/Nm, 200.1 Nm/tonne |
| Power | 401 Hp @ 5200 rpm |
| Torque | 629 Nm @ 4000 rpm, 463.93 lb.-ft. @ 4000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | L8T |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103.25 mm (4.06 in) |
| Piston Stroke | 98 mm (3.86 in) |
| Compression ratio | 10.8:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Direct injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 7.6 l (8.03 US qt | 6.69 UK qt) |
| Coolant | 14.6 l (15.43 US qt | 12.85 UK qt) |
| Kerb Weight | 3143 kg (6929.13 lbs) |
| Max. weight | 4695 kg (10350.7 lbs) |
| Max load | 1552 kg (3421.57 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 6577 kg (14499.8 lbs) |
| Length | 6127 mm (241.22 in) |
| Width including mirrors | 2079 mm (81.85 in) |
| Height | 2031 mm (79.96 in) |
| Wheelbase | 3795 mm (149.41 in) |
| Front track | 1731 mm (68.15 in) |
| Rear (Back) track | 1736 mm (68.35 in) |
| Ride height (ground clearance) | 258 mm (10.16 in) |
| 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 Allison |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Power steering | Hydraulic Steering |
| Tires size | 245/75 R17; 265/70 R17; 275/70 R18; 275/65 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Heavy-Duty Truck Heritage and the GMTT1XX Platform
The GMC Sierra has a long history as a robust and reliable work truck, dating back to the early days of GMC. The 2500HD model specifically is designed for demanding tasks, and the GMTT1XX platform, introduced in 2020 and facelifted in 2024, represents a significant evolution in this lineage. The facelift brought updated styling, enhanced technology, and refinements to the interior, aiming to improve the overall ownership experience while maintaining the truck’s core capabilities. The 2024 update focused on interior quality and technology integration, addressing some criticisms of earlier GMTT1XX models.
Engine and Transmission Details: The 6.6L L8T V8
The heart of this Sierra 2500HD variant is the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, direct-injected powerplant producing 401 horsepower and 464 lb-ft of torque. While not as fuel-efficient as some of the diesel options available in the Sierra 2500HD lineup, the gasoline V8 offers a lower initial cost and a familiar driving experience for those accustomed to gasoline engines. The 10-speed Allison automatic transmission is a key component, providing smooth and efficient power delivery, and contributing to the truck’s impressive towing capacity. The Allison transmission is known for its durability and ability to handle high torque loads, making it well-suited for heavy-duty applications.
Positioning within the Sierra 2500HD Lineup
The 6.6L V8 with the 10-speed automatic and 4WD configuration positions this Sierra 2500HD as a mid-range offering. GMC offers a 6.6L Duramax diesel engine as a more powerful, and fuel-efficient (though more expensive) option. The gasoline V8 provides a balance between cost, performance, and simplicity. Compared to the diesel, the V8 is generally favored by buyers who don’t require the absolute maximum towing capacity or who primarily use the truck for shorter distances and lighter-duty tasks. Trim levels available with this powertrain typically include SLE, Elevation, and AT4, offering varying levels of features and luxury.
Comparison with Siblings: Diesel vs. Gasoline
The most significant comparison for this variant is with the diesel-powered Sierra 2500HD. The Duramax diesel engine offers substantially more torque – typically around 975 lb-ft – making it the preferred choice for those who regularly tow very heavy loads. However, the diesel engine comes with a higher price tag, increased maintenance costs, and potentially more complex emissions systems. The gasoline V8, while offering less torque, is generally less expensive to maintain and repair. It also avoids the potential issues associated with diesel particulate filters and other emissions control components. The gasoline engine is also quieter and smoother in operation, offering a more refined driving experience for everyday use. The diesel is favored by commercial users and those who tow frequently, while the gasoline engine appeals to individuals and families who need a capable truck for occasional heavy-duty tasks and general transportation.
Technology and Features
The 2024 facelift brought several technological enhancements to the Sierra 2500HD. These include an updated infotainment system with a larger touchscreen display, improved connectivity features, and advanced driver-assistance systems such as automatic emergency braking, lane departure warning, and adaptive cruise control. The Double Cab configuration provides ample space for passengers, while the Standard Bed offers a practical cargo-carrying capacity. The interior materials and design were also upgraded to provide a more premium feel, addressing previous criticisms of the Sierra’s cabin quality. The truck also features GMC’s MultiPro tailgate, offering multiple configurations to enhance cargo loading and access.
Dimensions and Weight
With a length of 6127 mm (241.22 in) and a width of 2079 mm (81.85 in), the Sierra 2500HD Double Cab Standard Bed offers a substantial presence on the road. Its curb weight of 3143 kg (6929.13 lbs) reflects its heavy-duty construction. The maximum payload capacity of 1552 kg (3421.57 lbs) and a maximum trailer load of 6577 kg (14499.8 lbs) demonstrate its impressive capabilities. The relatively high ride height of 258 mm (10.16 in) provides good ground clearance for off-road use and navigating rough terrain.
