The GMC Sierra 2500HD, specifically the V (GMTT1XX) Crew Cab Standard Bed configuration equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower, represents a significant offering in the heavy-duty pickup truck segment. Produced from 2020 through 2023, this variant caters to buyers needing substantial towing and hauling capabilities combined with a degree of comfort and refinement. It sits within the broader Sierra 2500HD lineup as a premium offering, positioned above the gasoline-powered engines and often featuring more standard equipment than base work truck models.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD V (GMTT1XX) Crew Cab Standard Bed |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) 4WD Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.9 kg/Hp, 127.1 Hp/tonne |
| Weight-to-torque ratio | 2.8 kg/Nm, 352.4 Nm/tonne |
| Power | 445 Hp @ 2800 rpm |
| Power per litre | 67.4 Hp/l |
| Torque | 1234 Nm @ 1600 rpm (910.15 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax L5P |
| Engine displacement | 6604 cm3 (403 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103 mm (4.06 in.) |
| Piston Stroke | 99 mm (3.9 in.) |
| Compression ratio | 16:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | OHV |
| Engine oil capacity | 9.5 l (10.04 US qt | 8.36 UK qt) |
| Coolant | 29.1 l (30.75 US qt | 25.6 UK qt) |
| Kerb Weight | 3502 kg (7720.59 lbs.) |
| Max. weight | 5058 kg (11150.98 lbs.) |
| Max load | 1556 kg (3430.39 lbs.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 8392 kg (18501.19 lbs.) |
| Length | 6352 mm (250.08 in.) |
| Width including mirrors | 2079 mm (81.85 in.) |
| Height | 2027 mm (79.8 in.) |
| Wheelbase | 4037 mm (158.94 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1736 mm (68.35 in.) |
| Ride height (ground clearance) | 257 mm (10.12 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 | Coil spring, Double wishbone, Transverse stabilizer |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 350×40 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 | 265/70 R17; 245/75 R17; 265/70 R18; 265/60 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Sierra 2500HD variant is the 6.6-liter Duramax L5P turbo-diesel V8 engine. This engine represents a significant evolution of GMC’s diesel offerings, incorporating advanced technologies for increased power and efficiency. The L5P utilizes a cast iron block and aluminum cylinder heads, contributing to its robust construction. The engine employs a high-pressure common rail direct fuel injection system, delivering fuel directly into the cylinders at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) with an intercooler further enhances performance by providing increased air intake and reducing intake air temperature. The engine features an overhead valve (OHV) valvetrain, a design choice prioritizing durability and low-end torque. The Allison 10-speed automatic transmission is paired with the Duramax engine, providing smooth and efficient power delivery. This transmission is known for its durability and ability to handle the high torque output of the diesel engine.
Driving Characteristics
The 445 horsepower and 910 lb-ft of torque produced by the Duramax engine and 10-speed Allison transmission translate into impressive real-world performance. While not designed for outright speed, this Sierra 2500HD excels at towing and hauling heavy loads. The 10-speed transmission helps keep the engine in its optimal power band, providing strong acceleration even when loaded. Compared to the gasoline-powered 6.6L V8 option, the Duramax offers significantly more torque at lower RPMs, making it ideal for demanding tasks. The automatic transmission provides ease of use, especially for drivers unfamiliar with manual transmissions or those frequently operating in stop-and-go traffic. The ride quality, while firm due to the heavy-duty suspension, is generally comfortable, especially in the Crew Cab configuration.
Equipment & Trim Levels
The Sierra 2500HD Crew Cab Standard Bed with the Duramax engine was typically offered in higher trim levels such as SLE, SLT, and Denali. Standard features generally included a touchscreen infotainment system with Apple CarPlay and Android Auto compatibility, a rearview camera, and a suite of safety features. Higher trims added features like leather upholstery, heated and ventilated front seats, a premium sound system, and advanced driver-assistance systems such as adaptive cruise control and lane departure warning. Optional extras included a power sunroof, a rear-seat entertainment system, and various appearance packages.
Chassis & Braking
The Sierra 2500HD features a fully boxed frame designed for strength and rigidity. The front suspension utilizes coil springs and a double wishbone design with a transverse stabilizer bar, while the rear suspension employs a traditional leaf spring setup. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing heavy loads. ABS (Anti-lock Braking System) is standard. The heavy-duty suspension and braking system are specifically tuned to handle the increased weight and demands of a diesel-powered, heavy-duty pickup truck.
Market Reception & Comparison
The GMC Sierra 2500HD with the Duramax engine consistently received positive reviews for its towing capacity, performance, and refinement. Critics praised the engine’s power and efficiency, as well as the smooth operation of the Allison transmission. Compared to competitors like the Ford Super Duty and Ram 2500, the Sierra 2500HD was often seen as offering a more comfortable ride and a more upscale interior. Fuel economy, while improved over previous generations, remained relatively low compared to lighter-duty trucks, but was competitive within the heavy-duty segment. Reliability has generally been good, although diesel engines can be more expensive to maintain than gasoline engines due to the complexity of the fuel injection system and emissions controls.
Legacy
The Duramax L5P engine has proven to be a durable and reliable powertrain. In the used car market, Sierra 2500HD models equipped with this engine and transmission combination hold their value well, particularly those that have been well-maintained. The combination of power, towing capacity, and refinement makes this variant a popular choice for buyers seeking a capable and comfortable heavy-duty pickup truck. While newer models offer even more advanced features and technologies, the 2020-2023 Sierra 2500HD with the 6.6-liter Duramax remains a compelling option for those needing a workhorse truck that can handle demanding tasks.
