Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX) Crew Cab Standard Bed |
| Type (Engine) | 6.6 V8 (401 Hp) Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.5 kg/Hp, 133 Hp/tonne |
| Weight-to-torque ratio | 4.8 kg/Nm, 208.6 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 | 3015 kg (6646.94 lbs) |
| Max. weight | 4604 kg (10150.08 lbs) |
| Max load | 1589 kg (3503.15 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 4990 kg (11001.07 lbs) |
| Length | 6352 mm (250.08 in) |
| Width including mirrors | 2079 mm (81.85 in) |
| Height | 2054 mm (80.87 in) |
| Wheelbase | 4037 mm (158.94 in) |
| Front track | 1731 mm (68.15 in) |
| Rear (Back) track | 1736 mm (68.35 in) |
| Ride height (ground clearance) | 284 mm (11.18 in) |
| Drivetrain Architecture | 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 | 265/70 R17; 245/75 R17; 275/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
The GMC Sierra 3500HD V (GMTT1XX) Crew Cab Standard Bed, powered by the 6.6-liter V8 gasoline engine and paired with a six-speed automatic transmission, was a key component of GMC’s heavy-duty truck strategy. Introduced for the 2020 model year, this generation represented a significant redesign for the Sierra HD line, focusing on increased capability, improved interior refinement, and advanced technology. The GMTT1XX platform underpinned the Sierra 3500HD, sharing its core structure with the Chevrolet Silverado 3500HD. This particular configuration aimed to provide a balance between power, efficiency, and affordability within the heavy-duty truck segment.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD variant lies the GM 6.6-liter L8T V8 engine. This engine is a naturally aspirated, overhead valve (OHV) design featuring direct fuel injection and variable valve timing (VVT). The L8T produces 401 horsepower at 5200 rpm and 464 lb-ft of torque at 4000 rpm. The direct injection system optimizes combustion efficiency and power delivery. The six-speed Hydra-Matic automatic transmission was the sole transmission option for this engine. This transmission is known for its durability and smooth shifting characteristics, although it lacks the gear ratios found in some newer transmissions. The engine’s longitudinal mounting and rear-wheel-drive configuration are standard for heavy-duty trucks, allowing for optimal weight distribution and towing performance.
Driving Characteristics
The 6.6-liter V8 and six-speed automatic combination delivers a robust, if not overly refined, driving experience. Acceleration is adequate for a heavy-duty truck, but the focus is clearly on towing and hauling. The transmission’s gear ratios are well-suited for maintaining momentum when towing, but can feel somewhat conservative in everyday driving. Compared to the available Duramax diesel engine, the gasoline V8 offers quicker throttle response and a more familiar engine sound, but sacrifices fuel economy and ultimate towing capacity. The V8’s power delivery is linear and predictable, making it relatively easy to modulate when maneuvering in tight spaces or navigating challenging terrain.
Equipment & Trim Levels
The Sierra 3500HD V (GMTT1XX) Crew Cab Standard Bed was available in various trim levels, including SLE, SLT, and Denali. Even the base SLE trim offered a respectable level of standard equipment, including air conditioning, power windows and locks, a touchscreen infotainment system, and a rearview camera. Higher trims like the SLT added features such as leather upholstery, heated and ventilated front seats, a premium audio system, and advanced safety technologies. The Denali trim represented the pinnacle of luxury, with exclusive exterior and interior styling cues, along with a host of premium features. Optional extras included a power sunroof, a navigation system, and a bed liner.
Chassis & Braking
The Sierra 3500HD’s chassis is designed for heavy-duty use. It features a fully boxed frame constructed from high-strength steel. The front suspension utilizes coil springs and a double wishbone design, while the rear suspension employs a traditional leaf spring setup. This configuration provides a comfortable ride while maintaining excellent load-carrying capacity. Braking duties are handled by ventilated disc brakes at all four corners, providing ample stopping power even when towing a heavy trailer. An Anti-lock Braking System (ABS) is standard. Steering is accomplished via a hydraulic power steering system, offering a responsive and predictable feel.
Market Reception & Comparison
Critics generally praised the Sierra 3500HD’s robust construction, comfortable interior, and capable powertrain. However, the gasoline V8 engine was often criticized for its relatively low fuel economy compared to the diesel option. The V8-equipped models were seen as a good choice for buyers who didn’t require the maximum towing capacity of the diesel but still needed a capable heavy-duty truck. Compared to the diesel-powered Sierra 3500HD, the gasoline variant offered a lower initial purchase price and simpler maintenance requirements.
Legacy
The GMC Sierra 3500HD V (GMTT1XX) with the 6.6-liter V8 and six-speed automatic has proven to be a reliable and durable powertrain combination. While not as fuel-efficient as the diesel option, the gasoline engine has a reputation for longevity and relatively straightforward maintenance. In the used car market, these trucks remain popular among buyers seeking a capable and affordable heavy-duty pickup. The L8T engine is known for its robustness, and with proper maintenance, can provide many years of reliable service. The GMTT1XX platform itself is considered a solid and well-engineered design, contributing to the Sierra 3500HD’s enduring appeal.
