The Chevrolet Silverado 3500 HD IV (T1XX) Regular Cab Long Bed, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower and paired with an Allison 10-speed automatic transmission, represents a significant offering in the heavy-duty pickup truck segment. Produced from 2020 through 2023, this configuration catered to buyers needing substantial towing and hauling capabilities, primarily in the North American market. It occupied a position within the Silverado 3500 HD lineup as a work-focused, high-output variant, positioned above the gasoline-powered options and below the more luxurious trim levels.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD IV (T1XX) Regular Cab Long Bed |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) SRW Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.4 kg/Hp, 135.4 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 375.4 Nm/tonne |
| Power | 445 Hp @ 2800 rpm |
| Power per litre | 67.4 Hp/l |
| Torque | 1234 Nm @ 1600 rpm (910.15 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax L5P |
| Engine displacement | 6604 cm3 (403 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103 mm (4.06 in.) |
| Piston Stroke | 99 mm (3.9 in.) |
| Compression ratio | 16:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | OHV |
| Engine oil capacity | 9.5 l (10.04 US qt | 8.36 UK qt) |
| Coolant | 29.1 l (30.75 US qt | 25.6 UK qt) |
| Kerb Weight | 3287 kg (7246.59 lbs.) |
| Max. weight | 5216 kg (11499.31 lbs.) |
| Max load | 1929 kg (4252.72 lbs.) |
| Fuel tank capacity | 106 l (28 US gal | 23.32 UK gal) |
| Permitted trailer load with brakes (12%) | 9752 kg (21499.48 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 | 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 | 235/80 R17; 265/70 R17; 245/75 R17; 275/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
Introduction
The Chevrolet Silverado 3500 HD IV, specifically the Regular Cab Long Bed configuration with the 6.6L Duramax diesel and Allison automatic, debuted in 2020 as part of the fourth generation (T1XX platform) of Chevrolet’s heavy-duty truck lineup. This generation represented a significant overhaul, focusing on increased capability, improved interior refinement, and advanced technology. The Regular Cab/Long Bed combination was aimed at customers prioritizing maximum cargo space and towing capacity over passenger comfort, making it popular with tradespeople, farmers, and those frequently hauling large loads. This variant was a direct response to the growing demand for diesel-powered heavy-duty trucks capable of handling demanding tasks.
Powertrain & Engine Architecture
At the heart of this Silverado 3500 HD lies the Duramax L5P 6.6-liter turbocharged diesel V8 engine. This engine is a cornerstone of Chevrolet’s heavy-duty truck offerings, known for its robust construction and impressive torque output. The L5P utilizes a cast iron block, aluminum cylinder heads, and a forged steel crankshaft. It employs a diesel commonrail fuel injection system, delivering highly pressurized fuel directly into the cylinders for efficient combustion. The engine features an overhead valve (OHV) valvetrain, a design choice prioritizing durability and low-end torque. The turbocharger, coupled with an intercooler, forces more air into the engine, boosting power and efficiency. Paired with the engine is the Allison 10-speed automatic transmission, a heavy-duty unit designed to handle the immense torque produced by the Duramax. This transmission features electronically controlled shifts and a tow/haul mode optimized for maximizing towing performance. The 10-speed configuration provides a wider range of gear ratios, improving both acceleration and fuel economy.
Driving Characteristics
The 445 horsepower and 910 lb-ft of torque delivered by the Duramax/Allison combination translate into substantial real-world performance. While not designed for outright speed, this Silverado 3500 HD excels at accelerating with heavy loads. The Allison 10-speed automatic transmission is a key contributor to this capability, providing smooth and precise shifts. The gear ratios are optimized for towing, allowing the engine to stay within its peak torque band even when climbing hills or hauling trailers. Compared to the gasoline-powered Silverado 3500 HD models, the diesel variant offers significantly more low-end torque, making it easier to start and maintain momentum with heavy loads. Compared to higher-output Duramax variants (available in other Silverado trims), this 445 hp version offers a balance between power and fuel efficiency, making it a practical choice for everyday use.
Equipment & Trim Levels
The Regular Cab/Long Bed 3500 HD with the Duramax engine typically came standard with a functional, work-oriented interior. Standard features included vinyl or cloth upholstery, a basic infotainment system with a touchscreen display, and air conditioning. Higher trim levels, such as the LT and High Country, added features like leather upholstery, heated and ventilated seats, a premium audio system, and advanced safety technologies. Optional extras included a gooseneck/fifth-wheel hitch, bed liner, and various towing packages. The Regular Cab configuration prioritized functionality over luxury, offering a spacious work environment for the driver and a single passenger.
Chassis & Braking
The Silverado 3500 HD IV utilizes a fully boxed frame constructed from high-strength steel, providing a solid foundation for heavy-duty use. The front suspension features an independent torsion bar setup with double wishbones, while the rear suspension employs a traditional leaf spring design. This configuration balances ride comfort with load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing heavy loads. An Anti-lock Braking System (ABS) is standard. The rear axle is a solid axle, designed to withstand the stresses of heavy hauling. Steering is accomplished via a hydraulic power steering system.
Market Reception & Comparison
The 2020-2023 Silverado 3500 HD with the 6.6L Duramax and Allison automatic received generally positive reviews. Critics praised its impressive towing capacity, robust powertrain, and improved interior compared to previous generations. Fuel economy, while not exceptional, was considered competitive for a heavy-duty diesel truck. Compared to the gasoline-powered Silverado 3500 HD models, the Duramax variant commanded a higher price but offered significantly more torque and towing capability. Compared to rival trucks like the Ford Super Duty and Ram Heavy Duty, the Silverado 3500 HD was often seen as a strong contender, offering a compelling combination of capability, reliability, and value.
Legacy
The Duramax L5P engine and Allison 10-speed automatic transmission have proven to be a reliable and durable powertrain combination. These trucks maintain a strong presence in the used car market, commanding relatively high resale values due to their reputation for dependability and capability. While diesel engines require more diligent maintenance than their gasoline counterparts, the Duramax L5P has a track record of longevity when properly maintained. The Silverado 3500 HD IV with this powertrain continues to be a popular choice for buyers seeking a capable and reliable heavy-duty truck for work or recreational purposes.
