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 tasks like towing and hauling. The Regular Cab Long Bed configuration, specifically equipped with the 6.6-liter V8 engine producing 401 horsepower and paired with a 10-speed Allison automatic transmission and four-wheel drive (DRW – Dual Rear Wheel), represents a work-focused variant within the Sierra 3500HD lineup. Production began in 2024, building upon the foundation laid by previous generations while incorporating updated technology and styling.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Regular Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) 4WD DRW Automatic |
| Start of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.9 kg/Hp, 126 Hp/tonne |
| Weight-to-torque ratio | 5.1 kg/Nm, 197.7 Nm/tonne |
| Power | 401 Hp @ 5200 rpm |
| Torque | 629 Nm @ 4000 rpm, 463.93 lb.-ft. @ 4000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | L8T |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103.25 mm (4.06 in) |
| Piston Stroke | 98 mm (3.86 in) |
| Compression ratio | 10.8:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Direct injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 7.6 l (8.03 US qt | 6.69 UK qt) |
| Coolant | 14.6 l (15.43 US qt | 12.85 UK qt) |
| Kerb Weight | 3182 kg (7015.11 lbs) |
| Max. weight | 6350 kg (13999.35 lbs) |
| Max load | 3168 kg (6984.24 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 8380 kg (18474.74 lbs) |
| Length | 6002 mm (236.3 in) |
| Width including mirrors | 2457 mm (96.73 in) |
| Height | 2038 mm (80.24 in) |
| Wheelbase | 3595 mm (141.54 in) |
| Front track | 1731 mm (68.15 in) |
| Rear (Back) track | 1905 mm (75 in) |
| Ride height (ground clearance) | 266 mm (10.47 in) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| 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 | 235/80 R17; 235/80 R18 |
| Wheel rims size | 6.5J x 17 |
Introduction
The 2024 GMC Sierra 3500HD Regular Cab Long Bed with the 6.6L V8 and 4WD DRW configuration is positioned as a robust, no-frills work truck within the Sierra 3500HD range. It caters to buyers prioritizing maximum towing and payload capacity over luxury features. The GMTT1XX platform, representing the fifth generation of the Sierra/Silverado HD series, benefits from a comprehensive redesign for 2024, focusing on enhanced capability, technology, and interior refinement, though the Regular Cab Long Bed maintains a more utilitarian focus. This model is a direct competitor to Ford’s F-350 and Ram’s 3500 heavy-duty trucks.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD lies the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, overhead valve (OHV) design featuring direct fuel injection. The direct injection system optimizes combustion efficiency and power delivery. The engine produces 401 horsepower at 5200 rpm and 629 lb-ft of torque at 4000 rpm. The engine’s robust construction and relatively simple design contribute to its durability and reliability. The engine is mated to a 10-speed Allison automatic transmission, a heavy-duty unit known for its smooth shifting and ability to handle high torque loads. This transmission is electronically controlled, optimizing gear selection based on driving conditions and driver input. The Dual Rear Wheel (DRW) configuration significantly increases stability and load-carrying capacity.
Driving Characteristics
The combination of the 6.6L V8 and the 10-speed Allison transmission delivers a capable, albeit not particularly sporty, driving experience. The focus is squarely on work. Acceleration is adequate for a heavy-duty truck, but the emphasis is on providing strong low-end torque for towing and hauling. The 10-speed transmission helps keep the engine in its optimal power band, even when carrying a heavy load. Compared to higher-output diesel variants, this gasoline-powered model offers less overall torque, but it is generally quieter and less expensive to maintain. The DRW setup provides enhanced stability, particularly when towing, but it also increases the vehicle’s width, requiring more caution when maneuvering in tight spaces. The gear ratios are optimized for pulling power, meaning highway cruising RPMs are slightly higher than in some competitor models.
Equipment & Trim Levels
The Regular Cab Long Bed configuration typically represents the base level of the Sierra 3500HD lineup. Standard features generally include basic cloth upholstery, a functional dashboard layout with essential gauges, and a user-friendly infotainment system. Air conditioning is standard, but many luxury features found in higher trims (leather seats, premium audio systems, advanced driver-assistance systems) are either optional or unavailable. The focus is on providing a durable and functional interior that can withstand the rigors of work. Optional extras might include a trailer brake controller, upgraded audio, and basic convenience packages.
Chassis & Braking
The Sierra 3500HD utilizes a robust chassis designed to handle heavy loads. The front suspension features an independent torsion bar setup with double wishbones, providing a comfortable ride even when unladen. 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, measuring 355x40mm. An Anti-lock Braking System (ABS) is standard. The steering system is a hydraulic power-assisted cone worm with recirculation balls, providing a direct and responsive feel. The DRW configuration necessitates a wider track width, contributing to increased stability.
Market Reception & Comparison
Critics generally view the 6.6L V8/10-speed automatic combination as a viable option for buyers who don’t require the ultimate towing capacity of a diesel engine. Fuel economy is typically lower than diesel counterparts, but the initial purchase price is significantly less. Compared to the Duramax diesel engine offered in the Sierra 3500HD, this gasoline variant provides a simpler and potentially more reliable powertrain, albeit with reduced torque. The gasoline engine is often favored by those who primarily use the truck for local hauling and occasional towing, where the higher fuel costs are offset by the lower purchase price and maintenance expenses.
Legacy
The 6.6L V8 engine has a long-standing reputation for durability and reliability within the GMC and Chevrolet heavy-duty truck lineups. While not as fuel-efficient as modern diesel engines, it remains a popular choice for buyers seeking a cost-effective and dependable work truck. On the used car market, Sierra 3500HD models equipped with this powertrain generally hold their value well, particularly those that have been well-maintained. The Allison 10-speed automatic transmission is also known for its longevity and smooth operation, further enhancing the long-term appeal of this powertrain combination.
