The GMC Sierra 3500HD, in its fifth generation (GMTT1XX), received a significant refresh for the 2024 model year. This iteration continues GMC’s tradition of offering a heavy-duty pickup truck geared towards demanding work and towing applications. The Regular Cab Long Bed configuration, paired with the 6.6-liter Duramax Turbo-Diesel V8 engine producing 470 horsepower and utilizing a 10-speed Allison automatic transmission, represents a potent combination focused on capability and durability. This specific variant occupies a position in the lineup aimed at buyers prioritizing maximum towing capacity and diesel efficiency over luxury appointments, though it still offers a comfortable and well-equipped cabin for a work-focused truck.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Regular Cab Long Bed |
| Type (Engine) | 6.6 Duramax TD V8 (470 Hp) SRW Automatic |
| Start of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 6.7 kg/Hp, 148.5 Hp/tonne |
| Weight-to-torque ratio | 2.4 kg/Nm, 417.8 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 | 3164 kg (6975.43 lbs.) |
| Max. weight | 5216 kg (11499.31 lbs.) |
| Max load | 2052 kg (4523.89 lbs.) |
| Fuel tank capacity | 106 l (28 US gal | 23.32 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 | 2056 mm (80.94 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) | 285 mm (11.22 in.) |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine (ICE) drives the rear wheels. |
| 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 diesel engine. This engine is a turbocharged, overhead valve (OHV) V8, known for its robust construction and high torque output. The L5P utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) and intercooler work in tandem to maximize power and efficiency. The engine’s 16:1 compression ratio contributes to its thermal efficiency. The 10-speed Allison automatic transmission is specifically calibrated for the Duramax engine, providing smooth and efficient power delivery. This transmission features electronically controlled shifts and a wide gear ratio spread, optimizing both towing performance and fuel economy. The Allison transmission is renowned for its durability and ability to handle the high torque output of the Duramax engine.
Driving Characteristics
The 2024 Sierra 3500HD with the 6.6L Duramax and 10-speed Allison delivers a driving experience focused on capability rather than outright speed. While 470 horsepower is substantial, the engine’s strength lies in its massive 1322 lb-ft of torque. This translates to effortless towing and hauling, even with substantial loads. The 10-speed Allison transmission keeps the engine in its optimal power band, providing strong acceleration even when heavily laden. Compared to gasoline-powered Sierra 3500HD models, the Duramax offers significantly improved fuel economy, especially when towing. Compared to higher-output Duramax variants, this 470 hp version prioritizes a balance between power and efficiency, making it a good choice for those who frequently tow but don’t always need maximum power. The ride quality, while firm due to the heavy-duty suspension, is surprisingly comfortable, even when unladen.
Equipment & Trim Levels
The Regular Cab Long Bed 3500HD typically comes standard with features geared towards work-truck functionality. This includes a durable vinyl interior, air conditioning, a basic infotainment system with a touchscreen display, and power windows and locks. Higher trim levels, such as the SLE or Denali, add features like leather upholstery, heated and ventilated seats, a premium audio system, and advanced safety technologies. Optional extras for this variant include a trailer brake controller, a fifth-wheel hitch, and various bed accessories. The base trim focuses on providing essential features at a competitive price point, while optional packages allow buyers to customize the truck to their specific needs.
Chassis & Braking
The Sierra 3500HD utilizes a robust chassis designed to withstand heavy loads and demanding work conditions. The front suspension features an independent torsion bar setup with double wishbones, providing a comfortable ride and good 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. The front brakes measure 355×40 mm, while the rear brakes are 360×34 mm. An Anti-lock Braking System (ABS) is standard, enhancing safety and control. The steering system utilizes a cone worm with recirculation balls, providing precise and responsive steering feel.
Market Reception & Comparison
The 2024 GMC Sierra 3500HD with the 6.6L Duramax and 10-speed Allison has been well-received by critics and buyers alike. It’s praised for its exceptional towing capacity, strong fuel economy, and comfortable ride. Compared to competitors like the Ford Super Duty and Ram 3500, the Sierra 3500HD offers a compelling combination of capability and refinement. The Duramax engine is consistently ranked among the best diesel engines in the heavy-duty truck segment. While the initial purchase price is higher than gasoline-powered models, the Duramax’s fuel efficiency and longevity can offset the cost over the long term. Reliability reports generally indicate that the L5P Duramax engine is a durable and dependable powertrain.
Legacy
The L5P Duramax engine has established a strong reputation for reliability and longevity. Properly maintained, these engines can easily exceed 200,000 miles. On the used car market, Sierra 3500HD models equipped with the Duramax engine command a premium price due to their proven durability and towing capability. The 10-speed Allison transmission has also proven to be a reliable and robust component. This combination of engine and transmission continues to be a popular choice for buyers seeking a heavy-duty truck that can handle demanding work and provide years of dependable service. The 2024 refresh further solidifies the Sierra 3500HD’s position as a leading contender in the heavy-duty truck segment.
