The Chevrolet Silverado 3500 HD IV (T1XX) Crew Cab Long Bed, 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 comfortable and well-equipped cabin. It builds upon the foundation of the T1XX platform, introduced to enhance strength, refinement, and technology integration in Chevrolet’s heavy-duty offerings.
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 SRW 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 | 8.3 kg/Hp, 120.6 Hp/tonne |
| Weight-to-torque ratio | 3 kg/Nm, 334.4 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 | 3690 kg (8135.06 lbs.) |
| Max. weight | 5557 kg (12251.09 lbs.) |
| Max load | 1867 kg (4116.03 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%) | 9543 kg (21038.71 lbs.) |
| Length | 6759 mm (266.1 in.) |
| Width including mirrors | 2079 mm (81.85 in.) |
| Height | 2049 mm (80.67 in.) |
| Wheelbase | 4369 mm (172.01 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1736 mm (68.35 in.) |
| Ride height (ground clearance) | 283 mm (11.14 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, 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 |
Powertrain & Engine Architecture
At the heart of this Silverado 3500 HD variant lies the Duramax L5P 6.6-liter V8 diesel engine. This engine is a turbocharged, overhead valve (OHV) design, renowned for its durability and substantial torque output. The L5P utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) and intercooler further enhance performance and efficiency. The engine produces 445 horsepower at 2800 rpm and a massive 910 lb-ft (1234 Nm) of torque at 1600 rpm. This torque figure is crucial for heavy towing and hauling. The engine’s robust construction features a cast iron block and aluminum cylinder heads. The Allison 10-speed automatic transmission is specifically calibrated to handle the engine’s high torque output, providing smooth and efficient power delivery. This transmission replaced the previous 6-speed Allison in 2020, offering closer gear ratios for improved acceleration and towing performance.
Driving Characteristics
The combination of the 445 hp Duramax and the 10-speed Allison results in a driving experience that prioritizes capability over outright speed. While not a sports truck, the Silverado 3500 HD delivers confident acceleration, even when heavily loaded. The 10-speed transmission keeps the engine within its optimal power band, minimizing turbo lag and maximizing efficiency. Compared to the 6.6L gasoline engine option, the Duramax provides significantly more low-end torque, making it ideal for towing large trailers or hauling heavy payloads. Compared to lower-output Duramax variants, the 445 hp version offers a noticeable increase in power, particularly when merging onto highways or climbing steep grades. The four-wheel-drive system provides enhanced traction in challenging conditions, while the hydraulic steering offers a substantial feel, though it lacks the finesse of some newer electric power steering systems.
Equipment & Trim Levels
The Silverado 3500 HD IV Crew Cab Long Bed with the Duramax engine typically came in higher trim levels, such as LTZ or High Country. Standard features included a spacious crew cab with seating for five, a user-friendly infotainment system with Apple CarPlay and Android Auto compatibility, and a suite of safety features like automatic emergency braking and lane departure warning. Higher trims added luxury features such as leather upholstery, heated and ventilated front seats, a premium sound system, and advanced trailering technologies. Optional extras included a power sunroof, a rear-seat entertainment system, and various appearance packages.
Chassis & Braking
The Silverado 3500 HD features a fully boxed frame constructed from high-strength steel, providing a solid foundation for heavy-duty applications. 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, with larger rotors and calipers compared to lighter-duty Silverado models. An Anti-lock Braking System (ABS) is standard. The rear axle is a solid axle, optimized for strength and durability. Stabilizer bars are fitted to both the front and rear axles to reduce body roll during cornering.
Market Reception & Comparison
The 2020-2023 Silverado 3500 HD with the 6.6L Duramax and 10-speed Allison received generally positive reviews. Critics praised its powerful engine, smooth transmission, and impressive towing capabilities. Fuel economy, while not exceptional, was considered reasonable for a heavy-duty truck of its size and capability. Compared to competitors like the Ford Super Duty and Ram 3500, the Silverado 3500 HD offered a competitive combination of performance, features, and value. Some reviewers noted that the interior design, while functional, lacked the refinement of some competitors. Reliability reports have been generally positive, with the Duramax engine proving to be a durable and long-lasting powerplant.
Legacy
The 6.6L Duramax L5P engine paired with the Allison 10-speed automatic has established itself as a highly regarded powertrain in the heavy-duty truck segment. Its combination of power, torque, and durability has made it a popular choice among owners who require a reliable and capable workhorse. On the used car market, these Silverado 3500 HD models hold their value well, particularly those in good condition with well-documented maintenance histories. The L5P Duramax continues to be a sought-after engine, and well-maintained examples are expected to remain reliable for many years to come.
