The GMC Sierra 3500HD, specifically the V (GMTT1XX) Regular Cab Long Bed configuration powered by the 6.6-liter V8 engine producing 401 horsepower, represents a significant offering in the heavy-duty pickup truck segment. Introduced for the 2020 model year and continuing through 2023, this variant catered to buyers needing substantial towing and hauling capabilities without the added complexity or cost of higher trim levels. It occupied a crucial position in the Sierra 3500HD lineup, serving as a work-focused option for commercial users and individuals requiring serious truck functionality. This model year marked the beginning of the fourth generation for the Sierra HD series, bringing with it a substantial redesign and updated technology.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX) Regular Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) SRW Automatic |
| Start of production | 2020 year |
| End of production | 2023 year |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7 kg/Hp, 141.9 Hp/tonne |
| Weight-to-torque ratio | 4.5 kg/Nm, 222.6 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, VVT |
| 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 | 2826 kg / 6230.26 lbs |
| Max. weight | 4876 kg / 10749.74 lbs |
| Max load | 2050 kg / 4519.48 lbs |
| Fuel tank capacity | 136 l / 35.93 US gal | 29.92 UK gal |
| Permitted trailer load with brakes (12%) | 6577 kg / 14499.8 lbs |
| Length | 5982 mm / 235.51 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 | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission Hydra-Matic |
| Front suspension | Coil spring, Double wishbone, Transverse stabilizer |
| 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 | 235/80 R17; 265/70 R17; 245/75 R17; 275/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD variant lies the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, overhead valve (OHV) design featuring variable valve timing (VVT). Direct fuel injection is employed to optimize combustion efficiency and power output. The engine produces 401 horsepower at 5200 rpm and 464 lb-ft of torque at 4000 rpm. The engine’s robust construction and relatively simple design contribute to its reputation for durability. The powertrain is coupled with a six-speed Hydra-Matic automatic transmission, chosen for its ability to handle the high torque output and provide smooth shifting in demanding conditions. This transmission is known for its reliability and is a common choice in heavy-duty applications.
Driving Characteristics
The 6.6L V8 with the six-speed automatic delivers a driving experience focused on capability rather than outright speed. Acceleration is adequate for everyday driving and hauling loads, but it’s not particularly brisk. The automatic transmission is tuned for work, prioritizing smooth shifts and maintaining engine power within the optimal torque band. The gear ratios are optimized for towing and hauling, providing ample low-end torque. Compared to the available Duramax diesel engine, this gasoline variant offers less torque and lower fuel economy, but it provides a quieter and less expensive entry point into the heavy-duty truck market. Manual transmission options were not available with this engine configuration.
Equipment & Trim Levels
The Regular Cab Long Bed 3500HD with the 6.6L V8 typically came with a relatively basic level of standard equipment, reflecting its position as a work-oriented trim. Standard features generally included air conditioning, a basic infotainment system with a touchscreen display, and vinyl upholstery. Optional extras could include power windows and locks, upgraded audio systems, and various towing packages. The interior was designed for durability and ease of cleaning, prioritizing functionality over luxury. The long bed configuration provided ample cargo space for hauling materials and equipment.
Chassis & Braking
The Sierra 3500HD features a robust chassis designed to withstand heavy loads and demanding conditions. The front suspension utilizes a coil spring, double wishbone setup with a transverse stabilizer bar, while the rear suspension employs a traditional leaf spring rigid axle configuration. This setup provides a comfortable ride while maintaining excellent load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, with larger rotors at the front (355×40 mm) compared to the rear (360×34 mm). An Anti-lock Braking System (ABS) is standard. The steering system is a hydraulic recirculating ball setup, providing a solid and predictable feel.
Market Reception & Comparison
The 6.6L V8-powered Sierra 3500HD received mixed reviews. Critics acknowledged its strong towing and hauling capabilities but often pointed to its lower fuel economy compared to the diesel option. It was generally seen as a good value for buyers who didn’t require the ultimate in towing capacity or fuel efficiency. Compared to the diesel-powered models, this variant was significantly less expensive to purchase, making it an attractive option for budget-conscious buyers. Its simplicity and relative ease of maintenance were also seen as advantages.
Legacy
The 6.6L V8 engine in the GMTT1XX Sierra 3500HD has proven to be a relatively reliable powertrain. While not as fuel-efficient as the diesel alternatives, it has earned a reputation for durability and longevity. In the used car market, these trucks remain popular among those seeking a capable and affordable heavy-duty pickup. Maintenance is generally straightforward, and parts availability is good. However, potential buyers should be aware of the higher fuel consumption and the potential for oil consumption as the engine ages. Overall, the 2020-2023 GMC Sierra 3500HD with the 6.6L V8 and automatic transmission represents a solid and dependable work truck that continues to offer value in the used vehicle market.
