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 heavy-duty work truck designed for demanding tasks. Produced from 2020 to 2023, this variant occupied a significant position within the Sierra 3500HD lineup, catering to buyers needing substantial towing and payload capacity. It was positioned as a robust, no-nonsense solution for commercial use and serious recreational towing, falling between the lighter-duty 2500HD and the more specialized configurations of the 3500HD range.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX) Regular Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) DRW Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.4 kg/Hp, 135.6 Hp/tonne |
| Weight-to-torque ratio | 4.7 kg/Nm, 212.7 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, 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 | 2957 kg (6519.07 lbs) |
| Max. weight | 6350 kg (13999.35 lbs) |
| Max load | 3393 kg (7480.28 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 7620 kg (16799.22 lbs) |
| Length | 5982 mm (235.51 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 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, 355×40 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Power steering | Hydraulic Steering |
| Tires size | 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 lies the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, overhead valve (OHV) design featuring direct fuel injection and variable valve timing (VVT). The L8T is known for its robust construction and ability to deliver substantial torque at lower RPMs, crucial for heavy hauling. The engine’s direct injection system optimizes combustion efficiency and power output. The Hydra-Matic 6-speed automatic transmission was the standard pairing for this engine. This transmission is designed to handle the high torque output of the V8 and provide smooth, reliable shifting under heavy loads. The transmission’s gear ratios are optimized for towing, with a lower first gear for quick acceleration when loaded and higher gears for efficient highway cruising.
Driving Characteristics
The 401 horsepower and 464 lb-ft of torque delivered by the 6.6L V8, coupled with the 6-speed automatic, provided a capable, though not particularly sporty, driving experience. Acceleration was adequate for a vehicle of this size and weight, but the focus was clearly on usability and towing capacity. Compared to the available Duramax diesel engine options, the gasoline V8 offered less torque, resulting in a slightly lower maximum towing capacity. However, the gasoline engine was generally quieter and less expensive to maintain, appealing to buyers who didn’t require the absolute maximum towing capability. The automatic transmission shifted smoothly, but could sometimes feel hesitant when downshifting under heavy load. The long bed configuration contributed to a comfortable ride, absorbing bumps and providing a stable platform for hauling.
Equipment & Trim Levels
The Sierra 3500HD Regular Cab Long Bed with the 6.6L V8 typically came standard with features geared towards work and utility. This included a basic infotainment system, air conditioning, vinyl upholstery, and a heavy-duty suspension. Higher trim levels, such as the SLE and Denali, added features like leather upholstery, upgraded infotainment systems with larger touchscreens, heated and ventilated seats, and advanced safety technologies. Optional extras included a trailer brake controller, a fifth-wheel hitch, and various bed accessories. The Regular Cab configuration prioritized functionality over passenger comfort, offering a spacious work area but limited rear seating.
Chassis & Braking
The Sierra 3500HD’s chassis was built for durability and heavy-duty use. It featured a fully boxed frame and a robust suspension system designed to handle substantial payloads. The front suspension utilized coil springs and a double wishbone design, while the rear suspension employed leaf springs. This configuration provided a stable and controlled ride, even when heavily loaded. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power. An Anti-lock Braking System (ABS) was standard, enhancing safety and control during emergency braking situations. The rear axle was a dual rear wheel (DRW) configuration, further increasing stability and load-carrying capacity.
Market Reception & Comparison
The GMC Sierra 3500HD with the 6.6L V8 received generally positive reviews for its capability and reliability. Critics praised its robust construction and ability to handle demanding tasks. However, some noted that the gasoline engine’s fuel economy was lower than that of the diesel options. Compared to the Duramax diesel, the V8 offered a lower initial cost and simpler maintenance, making it an attractive option for buyers who didn’t need the diesel’s maximum towing capacity. The V8 also offered a quieter and smoother driving experience compared to the often-clattery diesel engines.
Legacy
The 6.6L L8T V8-powered Sierra 3500HD has proven to be a reliable and durable work truck. While the diesel variants are often favored for their ultimate towing capacity, the gasoline V8 remains a viable option for buyers seeking a capable and affordable heavy-duty truck. On the used car market, these trucks are generally well-regarded for their longevity and relatively straightforward maintenance. The GMTT1XX platform is known for its robust construction, and the L8T engine has a reputation for being relatively trouble-free, making these trucks a popular choice for those needing a dependable workhorse.
