The GMC Sierra 2500HD V, specifically the facelifted 2024 model year iteration based on the GMTT1XX platform, represents GMC’s heavy-duty full-size pickup truck offering. This particular variant features a Regular Cab with a Long Bed configuration, powered by a 6.6-liter V8 gasoline engine producing 401 horsepower and paired with a 10-speed automatic transmission and a four-wheel drive system. Introduced for the 2023 model year as part of a broader refresh of the Sierra HD line, this configuration caters to buyers needing substantial towing and hauling capacity in a more work-focused package. It occupies a position within the Sierra 2500HD lineup geared towards commercial users and those prioritizing capability over luxury, slotting below the more opulent Denali and AT4 trims.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD V (GMTT1XX, facelift 2024) Regular Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) 4WD Automatic |
| Start of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.4 kg/Hp, 135 Hp/tonne |
| Weight-to-torque ratio | 4.7 kg/Nm, 211.7 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 | 2971 kg (6549.93 lbs) |
| Max. weight | 4694 kg (10348.5 lbs) |
| Max load | 1723 kg (3798.56 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 | 6002 mm (236.3 in) |
| Width including mirrors | 2076 mm (81.73 in) |
| Height | 2030 mm (79.92 in) |
| Wheelbase | 3595 mm (141.54 in) |
| Front track | 1731 mm (68.15 in) |
| Rear (Back) track | 1736 mm (68.35 in) |
| Ride height (ground clearance) | 259 mm (10.2 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 |
Powertrain & Engine Architecture
At the heart of this Sierra 2500HD variant lies the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, overhead valve (OHV) design featuring direct fuel injection. The engine’s architecture prioritizes low-end torque, crucial for heavy-duty applications. The 10.8:1 compression ratio contributes to efficient combustion, while the direct injection system enhances power and fuel economy. The engine is mated to a 10-speed Allison automatic transmission, a robust unit known for its durability and smooth shifting. This transmission is specifically calibrated for heavy hauling and towing, offering close gear ratios to keep the engine in its optimal power band. The four-wheel drive system is a traditional part-time system, allowing the driver to select between two-wheel drive, four-wheel drive high, and four-wheel drive low for varying terrain and load conditions.
Driving Characteristics
The 401 horsepower and 464 lb-ft of torque delivered by the 6.6L V8, combined with the 10-speed automatic, provide ample power for demanding tasks. While not as quick as lighter-duty pickups, the Sierra 2500HD offers strong acceleration, even when heavily loaded. The automatic transmission’s gear ratios are well-suited for towing, providing consistent power delivery and minimizing the need for frequent downshifts. Compared to the available Duramax diesel engine option, this gasoline V8 offers a different driving experience. The diesel provides significantly more torque at lower RPMs, making it ideal for extremely heavy towing, but the gasoline engine is quieter and generally less expensive to maintain. The ride quality, while firm due to the heavy-duty suspension, is acceptable for a truck of this size and capability.
Equipment & Trim Levels
The Regular Cab Long Bed 6.6L V8 4WD configuration typically comes standard with features geared towards work-truck functionality. This includes a basic infotainment system, vinyl upholstery, and manually adjustable seats. Standard safety features include ABS, stability control, and multiple airbags. Optional extras, depending on the package selected, could include a larger touchscreen display, upgraded audio system, power windows and locks, and a trailer brake controller. The interior is designed for durability and ease of cleaning, reflecting its intended use. The absence of many luxury features keeps the price point competitive for buyers prioritizing function over form.
Chassis & Braking
The Sierra 2500HD utilizes a body-on-frame construction, providing a robust platform for heavy-duty applications. The front suspension features an independent torsion bar setup with double wishbones, while the rear suspension employs a traditional leaf spring design. This configuration is optimized for load-carrying capacity and stability. The braking system consists of ventilated discs at all four wheels, with larger front discs (355×40 mm) than the rear (360×34 mm). The ABS system helps maintain control during hard braking. The heavy-duty chassis and braking system are designed to handle the substantial weight of the truck and its potential payloads.
Market Reception & Comparison
Critics generally viewed the 6.6L V8/10-speed automatic combination as a capable, if not exceptional, powertrain. It offered a good balance of power and fuel economy for a heavy-duty truck, but it didn’t match the sheer towing capacity of the Duramax diesel. Fuel economy is rated at around 14 MPG city and 17 MPG highway, which is typical for a gasoline-powered heavy-duty pickup. Reliability has been generally good, with the Allison transmission proving particularly durable. Compared to competitors like the Ford Super Duty and Ram 2500, the Sierra 2500HD offered a competitive package, with a focus on functionality and value.
Legacy
The GMTT1XX platform Sierra 2500HD, and specifically the 6.6L V8/10-speed automatic configuration, represents a solid and dependable work truck. While the diesel variants often command higher resale values, the gasoline-powered models remain popular in the used market due to their lower purchase price and simpler maintenance requirements. The Allison transmission is a key selling point, known for its longevity and ability to withstand heavy use. As these trucks age, proper maintenance of the fuel system and regular oil changes are crucial to ensure continued reliability. The 2024 facelift further enhanced the Sierra 2500HD’s appeal, solidifying its position as a capable and versatile heavy-duty pickup.
