The Chevrolet Silverado 3500 HD IV (T1XX) Crew Cab Long Bed, specifically equipped with the 6.6-liter Duramax V8 engine producing 445 horsepower and paired with a 10-speed automatic transmission and four-wheel drive, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2020 through 2023, this variant occupied a premium position within the Silverado 3500 HD lineup, targeting buyers requiring substantial towing and hauling capabilities alongside a degree of comfort and refinement. It’s part of the fourth generation (T1XX) of the Silverado HD series, known for its increased strength, advanced technology, and improved interior.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD IV (T1XX) Crew Cab Long Bed |
| Type (Engine) | 6.6 Duramax V8 (445 Hp) 4WD DRW Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8.5 kg/Hp, 118.2 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 327.8 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 | 3765 kg (8300.4 lbs.) |
| Max. weight | 6350 kg (13999.35 lbs.) |
| Max load | 2585 kg (5698.95 lbs.) |
| Trunk (boot) space – maximum | 2364 l (83.48 cu. ft.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 14143 kg (31179.98 lbs.) |
| Length | 6759 mm (266.1 in.) |
| Width including mirrors | 2457 mm (96.73 in.) |
| Height | 2049 mm (80.67 in.) |
| Wheelbase | 4369 mm (172.01 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1905 mm (75 in.) |
| Ride height (ground clearance) | 264 mm (10.39 in.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels 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, 355×40 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 Silverado 3500 HD variant is the Duramax L5P 6.6-liter V8 diesel engine. This engine, a staple in Chevrolet and GMC heavy-duty trucks for years, is renowned for its durability and substantial torque output. The L5P utilizes a cast iron block and aluminum cylinder heads, featuring a common-rail direct fuel injection system capable of extremely high injection pressures for optimized combustion. The engine employs an overhead valve (OHV) valvetrain, a design choice prioritizing low-end torque and reliability over high-revving performance. A single variable geometry turbocharger with an intercooler further enhances power and efficiency. The 10-speed Allison automatic transmission, a significant upgrade over previous generations, provides smooth and efficient power delivery, with closely spaced gear ratios optimized for both towing and highway cruising. This transmission is known for its robustness and ability to handle the engine’s immense torque.
Driving Characteristics
The combination of the 445 horsepower Duramax engine and the 10-speed Allison transmission results in a driving experience focused on effortless power and control. While not designed for sporty acceleration, the Silverado 3500 HD delivers strong, consistent torque from low RPMs, making it ideal for hauling heavy loads or navigating challenging terrain. The 10-speed transmission minimizes hunting for the right gear, providing smooth transitions and keeping the engine within its optimal power band. Compared to the gasoline-powered Silverado 3500 HD models, the Duramax diesel offers significantly more torque, making it the preferred choice for those who regularly tow trailers or carry substantial payloads. Compared to earlier Duramax engines, the 10-speed Allison provides improved fuel economy and a more refined driving experience.
Equipment & Trim Levels
The Crew Cab Long Bed configuration, combined with the Duramax engine, typically placed this Silverado 3500 HD in the higher trim levels, such as LTZ or High Country. Standard features generally included a premium infotainment system with a large touchscreen display, Apple CarPlay and Android Auto compatibility, leather upholstery, heated and ventilated front seats, and a comprehensive suite of safety features like automatic emergency braking and lane departure warning. Optional extras could include a power sunroof, a premium audio system, and advanced trailering technologies such as a bed view camera and trailer tire pressure monitoring. The Long Bed configuration provides ample cargo space, while the Crew Cab offers comfortable seating for five passengers.
Chassis & Braking
The Silverado 3500 HD features a fully boxed frame constructed from high-strength steel, providing a solid foundation for heavy-duty use. The front suspension utilizes 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. The ABS (Anti-lock Braking System) enhances stability and control during emergency braking situations. The Dual Rear Wheel (DRW) configuration, common with this engine and trim level, further increases stability and payload capacity.
Market Reception & Comparison
The Silverado 3500 HD with the Duramax engine consistently received positive reviews from automotive critics, praised for its powerful engine, smooth transmission, and comfortable ride. Fuel economy, while not a primary concern for heavy-duty truck buyers, was generally considered competitive within the segment. Compared to the gasoline-powered Silverado 3500 HD models, the Duramax diesel offered superior towing and hauling capabilities, albeit at a higher initial cost. Reliability has been generally good, although diesel engines can be more expensive to maintain than gasoline engines due to the complexity of the fuel injection system and emissions controls. Compared to competitors like the Ford Super Duty and Ram Heavy Duty, the Silverado 3500 HD offered a compelling combination of performance, features, and value.
Legacy
The 2020-2023 Chevrolet Silverado 3500 HD with the 6.6-liter Duramax engine and 10-speed Allison transmission has established itself as a reliable and capable workhorse in the used truck market. The Duramax L5P engine is known for its longevity, and with proper maintenance, these trucks can provide many years of service. The 10-speed Allison transmission has also proven to be durable and dependable. Demand for these trucks remains strong, particularly among buyers seeking a heavy-duty truck with proven towing and hauling capabilities. The combination of power, comfort, and technology makes this Silverado 3500 HD variant a desirable choice for both commercial and personal use.

