The GMC Sierra 3500HD, in its fifth generation (GMTT1XX), received a significant facelift for the 2024 model year. This iteration represents GMC’s heavy-duty pickup truck offering, positioned above the Sierra 1500 and designed for demanding tasks such as towing and hauling. The Double Cab Long Bed configuration, paired with the 6.6-liter Duramax Turbo Diesel V8 engine producing 470 horsepower and coupled with a 10-speed Allison automatic transmission and four-wheel drive, represents a premium and capable trim level within the 3500HD lineup. This specific variant caters to buyers needing substantial capability without sacrificing everyday usability.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Double Cab Long Bed |
| Type (Engine) | 6.6 Duramax TD V8 (470 Hp) 4WD DRW 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 | 7.9 kg/Hp, 127.1 Hp/tonne |
| Weight-to-torque ratio | 2.8 kg/Nm, 357.4 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 | 3699 kg (8154.9 lbs.) |
| Max. weight | 6350 kg (13999.35 lbs.) |
| Max load | 2651 kg (5844.45 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 | 6534 mm (257.24 in.) |
| Width including mirrors | 2457 mm (96.73 in.) |
| Height | 2037 mm (80.2 in.) |
| Wheelbase | 4127 mm (162.48 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1905 mm (75 in.) |
| Ride height (ground clearance) | 264 mm (10.39 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, 355×40 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 |
INTRODUCTION
The 2024 GMC Sierra 3500HD Double Cab Long Bed with the 6.6L Duramax diesel and Allison transmission represents a significant upgrade in capability and refinement for GMC’s heavy-duty truck line. Built on the GMTT1XX platform, this model year’s facelift brought updated styling, enhanced technology, and continued improvements to the already robust Duramax engine. This configuration is aimed at buyers who require a powerful and versatile truck for work or recreational purposes, offering a balance between towing capacity, payload, and interior comfort. The Double Cab configuration provides ample space for passengers, while the Long Bed offers increased cargo capacity compared to the standard bed length.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD lies the L5P 6.6-liter Duramax turbocharged diesel V8 engine. This engine is a cornerstone of GMC’s heavy-duty lineup, known for its durability and impressive torque output. The engine utilizes a direct injection system with a common rail design, delivering fuel at extremely high pressures for optimized combustion. The valvetrain employs an overhead valve (OHV) configuration, a design choice favored for its robustness and simplicity. The turbocharger, coupled with an intercooler, significantly boosts power and efficiency. The 10-speed Allison automatic transmission is specifically calibrated to handle the immense torque produced by the Duramax engine, 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 combination of the 470 horsepower and 1322 lb-ft of torque, coupled with the 10-speed Allison transmission, results in a driving experience that is both powerful and surprisingly refined. The truck exhibits strong acceleration, even when loaded or towing. The Allison transmission’s closely spaced gear ratios ensure the engine remains within its optimal power band, providing consistent and responsive performance. Compared to gasoline-powered Sierra 3500HD models, the Duramax diesel offers significantly more low-end torque, making it ideal for hauling heavy loads and navigating challenging terrain. While not as quick off the line as some lighter-duty trucks, the Duramax provides a level of effortless pulling power that is unmatched. The four-wheel-drive system enhances traction in various conditions, providing confidence and control.
Equipment & Trim Levels
The 2024 Sierra 3500HD Double Cab Long Bed with the Duramax engine typically comes well-equipped, even in its base trim levels. Standard features often include a user-friendly infotainment system with a touchscreen display, Apple CarPlay and Android Auto compatibility, and a suite of advanced safety features such as automatic emergency braking and lane departure warning. Higher trim levels add features like leather upholstery, heated and ventilated front seats, a premium sound system, and advanced trailering technologies. The Double Cab configuration provides comfortable seating for five passengers, with ample legroom and headroom. Interior materials are generally durable and well-appointed, reflecting the truck’s premium positioning.
Chassis & Braking
The Sierra 3500HD features a robust chassis designed to withstand the stresses of heavy-duty use. The front suspension utilizes an independent torsion bar and double wishbone setup, providing a comfortable ride and precise handling. 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 heavy loads. The anti-lock braking system (ABS) helps maintain control during emergency braking situations. The truck’s heavy-duty frame and suspension components contribute to its impressive towing and payload capacities.
Market Reception & Comparison
The 2024 GMC Sierra 3500HD with the Duramax diesel engine has been well-received by critics and consumers alike. Reviewers praise its powerful engine, smooth transmission, and comfortable ride. Compared to other heavy-duty trucks in its class, such as the Ford Super Duty and Ram 3500, the Sierra 3500HD offers a competitive combination of capability, refinement, and technology. The Duramax engine is often lauded for its reliability and longevity. Fuel economy, while not a primary concern for heavy-duty truck buyers, is respectable for a vehicle of this size and capability. The Sierra 3500HD generally commands a slightly higher price than some of its competitors, reflecting its premium features and upscale interior.
Legacy
The Duramax diesel engine has established a strong reputation for reliability and durability over the years. The L5P version, found in the 2024 Sierra 3500HD, continues this legacy. These engines, when properly maintained, are known to exceed 200,000 miles with minimal issues. On the used car market, Sierra 3500HD models equipped with the Duramax diesel engine typically hold their value well, due to their proven performance and longevity. The 10-speed Allison transmission has also proven to be a reliable and durable component, further enhancing the long-term appeal of this powertrain combination. The 2024 facelifted model is expected to continue this trend, solidifying the Sierra 3500HD’s position as a leading contender in the heavy-duty truck segment.
