The GMC Sierra 3500HD, specifically the 2024 model year facelift in Crew Cab Long Bed configuration with the 6.6-liter V8 engine producing 401 horsepower and paired with a 10-speed automatic transmission and four-wheel drive (4WD), represents GMC’s heavy-duty full-size pickup truck offering. Introduced as part of the GMTT1XX generation, this variant caters to buyers needing substantial towing and payload capacity, blending robust capability with a degree of refinement expected in the modern truck market. This configuration sits towards the upper end of the Sierra 3500HD lineup, offering a balance between capability and everyday usability.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Crew Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) 4WD SRW Automatic |
| Start of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 8.1 kg/Hp, 123 Hp/tonne |
| Weight-to-torque ratio | 5.2 kg/Nm, 192.9 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 | 3261 kg (7189.27 lbs) |
| Max. weight | 5307 kg (11699.93 lbs) |
| Max load | 2046 kg (4510.66 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 7257 kg (15998.95 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 L8T V8 gasoline engine. This engine utilizes direct fuel injection, a technology that improves efficiency and power output by injecting fuel directly into the combustion chamber. The engine employs an overhead valve (OHV) valvetrain, a traditional design known for its durability and relatively compact size. The 10-speed Allison automatic transmission is a key component, offering a wide gear ratio spread for optimized towing and fuel economy. This transmission allows the engine to operate in its most efficient range more often, even under heavy loads. The 4WD system is a traditional part-time system, allowing the driver to switch between two-wheel drive and four-wheel drive as needed.
Driving Characteristics
The 401 horsepower and 464 lb-ft of torque provide substantial pulling power, making this Sierra 3500HD capable of handling demanding towing tasks. The 10-speed automatic transmission helps to manage this power effectively, providing smooth shifts and keeping the engine in its optimal power band. Compared to lower-output engine options, this V8 delivers significantly more acceleration and responsiveness, particularly when loaded. While not as fuel-efficient as the diesel options, the gasoline engine offers a different driving experience, with a more traditional V8 sound and feel. The long wheelbase and heavy-duty suspension contribute to a stable and controlled ride, even with a substantial payload.
Equipment & Trim Levels
The Crew Cab Long Bed configuration offers a spacious interior with seating for five passengers. Standard features typically include a user-friendly infotainment system with touchscreen display, Apple CarPlay and Android Auto compatibility, and a suite of safety features such as automatic emergency braking and lane departure warning. Higher trim levels add features like leather upholstery, heated and ventilated seats, a premium sound system, and advanced trailering technologies. Optional extras often include a power sunroof, upgraded wheels, and various appearance packages.
Chassis & Braking
The Sierra 3500HD utilizes a robust chassis designed to withstand heavy loads and demanding 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 at all four corners, providing ample stopping power. The ABS system helps to maintain control during emergency braking situations. The heavy-duty suspension and braking components are crucial for ensuring safe and stable operation when towing or hauling heavy loads.
Market Reception & Comparison
The 2024 GMC Sierra 3500HD with the 6.6L V8 and 10-speed automatic received generally positive reviews, with critics praising its powerful engine, smooth transmission, and comfortable ride. Compared to the diesel options, the gasoline engine was noted for its lower initial cost and quieter operation, but also for its lower fuel economy. Against competitors like the Ford Super Duty and Ram Heavy Duty, the Sierra 3500HD was seen as a strong contender, offering a compelling combination of capability, comfort, and technology. Reliability reports have been generally favorable, with the Allison transmission being particularly well-regarded for its durability.
Legacy
The GMTT1XX generation Sierra 3500HD, and specifically this 6.6L V8/10-speed automatic combination, represents a modern approach to heavy-duty truck design. While diesel engines remain dominant in this segment, the gasoline V8 offers a viable alternative for buyers who prioritize lower upfront cost and a more familiar driving experience. The Allison transmission’s proven reliability ensures that these trucks are likely to remain dependable workhorses for years to come. On the used car market, well-maintained examples of this configuration are expected to hold their value due to their capability and reputation for durability.
