The GMC Sierra 3500HD, in its fifth generation (GMTT1XX), received a significant facelift 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 a robust 1322 Nm (975.06 lb-ft) of torque, represents a potent combination within the Sierra 3500HD lineup. This particular variant is positioned as a work-focused trim, prioritizing capability over luxury, though modern amenities are still included. Production began in late 2023 for the 2024 model year.
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) 4WD 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 | 7.1 kg/Hp, 141.6 Hp/tonne |
| Weight-to-torque ratio | 2.5 kg/Nm, 398.3 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 | 3319 kg (7317.14 lbs.) |
| Max. weight | 5352 kg (11799.14 lbs.) |
| Max load | 2033 kg (4482 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 | 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 turbo-diesel V8 engine. This engine has been a mainstay in GMC and Chevrolet heavy-duty trucks for years, undergoing continuous refinement. The L5P utilizes a cast iron block and aluminum cylinder heads, contributing to its durability. It employs a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. The turbocharger, coupled with an intercooler, provides increased air density for enhanced power output. The engine features an overhead valve (OHV) valvetrain, a design choice prioritizing low-end torque and reliability. The 10-speed Allison automatic transmission is specifically calibrated to handle the engine’s substantial torque output, providing smooth and efficient gear changes. This transmission is known for its robustness and ability to withstand the stresses of heavy towing and hauling.
Driving Characteristics
The 2024 Sierra 3500HD with the 6.6L Duramax and 10-speed automatic delivers a driving experience focused on capability rather than sportiness. The engine provides ample low-end torque, making it ideal for towing heavy loads or navigating challenging terrain. While 470 horsepower is substantial, the engine’s strength lies in its ability to maintain consistent power delivery across a wide RPM range. The 10-speed Allison transmission’s gear ratios are optimized for both towing and fuel efficiency. Compared to gasoline-powered Sierra 3500HD models, this diesel variant offers significantly more torque, resulting in superior towing capacity. Compared to other Duramax configurations, the 470 hp version offers a balance between power and efficiency, sitting above the lower-output variants but below the highest-performance tunes available.
Equipment & Trim Levels
The Regular Cab Long Bed 3500HD typically comes standard with features geared towards work truck functionality. This includes a heavy-duty vinyl interior, basic infotainment system with a touchscreen display, and standard safety features like ABS and stability control. Optional extras often include upgraded infotainment systems with navigation, premium audio systems, power-adjustable seats, and various towing packages. The exterior typically features black bumpers and grille surrounds, emphasizing its work-oriented nature. Higher trim levels offer more luxurious appointments, but the base Regular Cab configuration prioritizes affordability and durability.
Chassis & Braking
The Sierra 3500HD utilizes a robust chassis designed to withstand heavy loads. The front suspension features an independent torsion bar setup with double wishbones, providing a comfortable ride while maintaining stability. The rear suspension employs a traditional leaf spring design, known for its durability and load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, with larger rotors at the front to provide increased stopping power. The braking system is assisted by ABS to prevent wheel lockup during hard braking. The truck’s substantial weight and heavy-duty suspension contribute to its stable and controlled handling, even when towing or hauling.
Market Reception & Comparison
The 2024 GMC Sierra 3500HD, particularly the Duramax diesel variants, consistently receives positive reviews for its towing capacity, durability, and overall capability. Critics often praise the Allison transmission for its smooth operation and reliability. Compared to competitors like the Ford Super Duty and Ram 3500, the Sierra 3500HD is often seen as a strong contender, offering a compelling combination of power, technology, and comfort. Fuel economy, while improved with the 10-speed transmission, remains a consideration for diesel trucks, but the Duramax engine generally offers competitive fuel efficiency within its class. Reliability has been generally good, with the Duramax engine proving to be a long-lasting powertrain.
Legacy
The Duramax diesel engine has established a strong reputation for longevity and reliability. The L5P variant, found in the 2024 Sierra 3500HD, is expected to continue this trend. These trucks, even with high mileage, often command strong resale values due to their proven durability and towing capabilities. The combination of the Duramax engine and Allison transmission is considered a benchmark in the heavy-duty truck segment, and these powertrains are likely to remain desirable in the used car market for years to come. Proper maintenance, including regular oil changes and fuel filter replacements, is crucial for maximizing the lifespan of this powertrain.
