The GMC Sierra 3500HD, specifically the 2024 model year facelift featuring the Crew Cab Long Bed configuration with the 6.6-liter Duramax Turbo Diesel V8 engine producing 470 horsepower, represents GMC’s heavy-duty pickup truck offering. Introduced as part of the GMTT1XX generation, this variant caters to buyers needing substantial towing and hauling capabilities combined with a degree of interior refinement. Production began in 2024, building upon the established reputation of the Sierra HD line for durability and performance in the North American truck market. This particular configuration sits at the upper end of the Sierra 3500HD lineup, offering a balance between capability and features, appealing to both commercial users and private owners requiring serious truck functionality.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Crew Cab Long Bed |
| Type (Engine) | 6.6 Duramax TD V8 (470 Hp) 4WD SRW Automatic |
| Start of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.6 kg/Hp, 131.1 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 368.9 Nm/tonne |
| Power | 470 Hp @ 2800 rpm |
| Power per litre | 71.2 Hp/l |
| Torque | 1322 Nm @ 1600 rpm (975.06 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | 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 | 28.5 l (30.12 US qt | 25.08 UK qt) |
| Kerb Weight | 3584 kg (7901.37 lbs.) |
| Max. weight | 5557 kg (12251.09 lbs.) |
| Max load | 1973 kg (4349.72 lbs.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 9072 kg (20000.34 lbs.) |
| Length | 6776 mm (266.77 in.) |
| Width including mirrors | 2079 mm (81.85 in.) |
| Height | 2049 mm (80.67 in.) |
| Wheelbase | 4369 mm (172.01 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1736 mm (68.35 in.) |
| Ride height (ground clearance) | 283 mm (11.14 in.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front 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 | 275/70 R18; 275/65 R20 |
| Wheel rims size | 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Sierra 3500HD is the 6.6-liter L5P Duramax turbocharged diesel V8 engine. This engine is a cornerstone of GMC’s heavy-duty lineup, known for its robust construction and high torque output. The L5P utilizes a cast iron block, aluminum cylinder heads, and a forged steel crankshaft, contributing to its longevity and ability to withstand high cylinder pressures. The engine employs a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion and reduced emissions. The turbocharger, coupled with an intercooler, provides increased air intake, boosting power and efficiency. The overhead valve (OHV) valvetrain, while a more traditional design, is favored for its durability and simplicity in a heavy-duty application. The Allison 10-speed automatic transmission is specifically calibrated to handle the engine’s substantial torque, providing smooth and efficient power delivery. This transmission features electronically controlled shifts and a tow/haul mode for optimized performance when towing heavy loads.
Driving Characteristics
The 470 horsepower and 1322 lb-ft of torque delivered by this powertrain configuration translate into impressive real-world performance. While not designed for outright speed, the Sierra 3500HD excels at accelerating with heavy loads. The 10-speed Allison transmission helps keep the engine in its optimal power band, providing strong acceleration even when fully loaded. Compared to lower-output gasoline engine options, the Duramax diesel offers significantly more low-end torque, making it ideal for towing and hauling. Compared to other Duramax variants, the 470 hp version provides a noticeable increase in power over earlier iterations, improving both acceleration and overall responsiveness. The automatic transmission, while convenient, may not offer the same level of control as a manual transmission, but it simplifies operation for a wider range of drivers.
Equipment & Trim Levels
The 2024 Sierra 3500HD Crew Cab Long Bed 6.6 Duramax typically comes standard with a comprehensive suite of features, including air conditioning, power windows and locks, a touchscreen infotainment system with Apple CarPlay and Android Auto compatibility, and a rearview camera. Higher trim levels, such as Denali, add premium features like leather upholstery, heated and ventilated seats, a premium sound system, and advanced safety technologies like adaptive cruise control and lane departure warning. Optional extras include a power sunroof, a rear-seat entertainment system, and various towing packages. The Crew Cab configuration provides ample space for passengers, while the Long Bed offers a generous cargo capacity.
Chassis & Braking
The Sierra 3500HD features a robust chassis designed to handle heavy loads. The front suspension utilizes an independent torsion bar and double wishbone setup, providing a comfortable ride and good handling characteristics. The rear suspension employs a traditional leaf spring design, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing. An Anti-lock Braking System (ABS) is standard. The steering system utilizes a hydraulic power steering setup, offering a responsive and precise feel. The truck’s substantial weight and long wheelbase contribute to its stability, particularly when towing.
Market Reception & Comparison
The GMC Sierra 3500HD with the Duramax diesel engine has consistently received positive reviews for its towing capacity, durability, and overall performance. Critics have praised the engine’s power and efficiency, as well as the Allison transmission’s smooth operation. Compared to gasoline-powered Sierra 3500HD models, the diesel variant offers superior fuel economy when towing heavy loads. Compared to competitors like the Ford Super Duty and Ram Heavy Duty, the Sierra 3500HD is often seen as offering a good balance of capability, comfort, and refinement. However, the diesel engine does come with a higher initial cost and potentially higher maintenance expenses.
Legacy
The Duramax diesel engine has established a strong reputation for reliability and longevity. Properly maintained, these engines can easily exceed 200,000 miles. The L5P variant, in particular, has proven to be a durable and capable powerplant. On the used car market, Sierra 3500HD models equipped with the Duramax diesel engine command a premium price due to their proven performance and towing capabilities. The 2024 facelifted model is expected to continue this legacy, offering a modern and capable heavy-duty truck for years to come.
