The Chevrolet Silverado 3500 HD IV (T1XX) Double Cab Long Bed, equipped with the 6.6-liter Duramax V8 engine producing 445 horsepower, represents a significant offering in the heavy-duty pickup truck segment. Produced from 2020 through 2023, this configuration occupied a premium position within the fourth generation (T1XX) Silverado HD lineup, catering to buyers requiring substantial towing and hauling capabilities alongside a degree of comfort and refinement. This particular variant, featuring a four-wheel-drive (4WD) dual rear wheel (DRW) setup and an Allison ten-speed automatic transmission, was designed for demanding work applications and recreational towing.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD IV (T1XX) Double 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 | 8.3 kg/Hp, 119.8 Hp/tonne |
| Weight-to-torque ratio | 3 kg/Nm, 332.3 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 | 3713 kg (8185.76 lbs.) |
| Max. weight | 6350 kg (13999.35 lbs.) |
| Max load | 2637 kg (5813.59 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%) | 14215 kg (31338.71 lbs.) |
| Length | 6514 mm (256.46 in.) |
| Width including mirrors | 2457 mm (96.73 in.) |
| Height | 2037 mm (80.2 in.) |
| Wheelbase | 4127 mm (162.48 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 |
INTRODUCTION
The Silverado 3500 HD IV, particularly the Double Cab Long Bed configuration with the Duramax 6.6L diesel, was introduced as part of the redesigned fourth generation in 2020. Built on the T1XX platform, this generation aimed to improve upon the previous model with increased space, enhanced technology, and greater capability. The 6.6L Duramax V8, paired with the Allison ten-speed automatic, was positioned as the premium powertrain option, targeting customers who frequently tow heavy loads, such as large trailers, fifth wheels, or commercial equipment. The DRW configuration further enhanced stability and payload capacity, making it a popular choice for professionals and serious enthusiasts.
Powertrain & Engine Architecture
The heart of this Silverado 3500 HD is the Duramax L5P 6.6-liter V8 diesel engine. This engine is a turbocharged, overhead valve (OHV) design featuring direct injection and a robust cast iron block. The L5P utilizes a Bosch common rail fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) and intercooler work in tandem to maximize power and efficiency. The engine produces 445 horsepower at 2800 rpm and a substantial 910 lb-ft (1234 Nm) of torque at 1600 rpm. This torque output is crucial for heavy towing and hauling. The Allison ten-speed automatic transmission is specifically tuned to handle the engine’s output, providing smooth and efficient power delivery. The transmission features electronically controlled shifts and a tow/haul mode that optimizes shift points for maximum towing performance.
Driving Characteristics
The Silverado 3500 HD with the Duramax and Allison transmission delivers a driving experience focused on capability and control. While not a performance-oriented truck, the engine provides ample power for accelerating with moderate loads. The ten-speed transmission helps keep the engine in its optimal power band, even when climbing hills or towing. Compared to the 6.6L gasoline engine option or the lower-output diesel variants, this configuration offers significantly more torque, resulting in superior towing and hauling performance. The DRW setup contributes to a more stable and controlled ride, especially when heavily loaded. However, the increased weight and length of the truck can make it less maneuverable in tight spaces compared to shorter wheelbase or single-rear-wheel configurations.
Equipment & Trim Levels
The Silverado 3500 HD IV offered various trim levels, with the Duramax/Allison combination typically found on LTZ, High Country, and Work Truck trims. Standard features on these trims included a large infotainment touchscreen with Apple CarPlay and Android Auto compatibility, a rearview camera, and a suite of driver-assistance technologies. Higher trims added features like leather upholstery, heated and ventilated front seats, a premium sound system, and advanced trailering technology. Optional extras included a power sunroof, a bed liner, and various off-road packages. The Double Cab configuration provided comfortable seating for five passengers, making it suitable for both work and family use.
Chassis & Braking
The Silverado 3500 HD features a fully boxed frame designed for strength and rigidity. The front suspension utilizes an independent torsion bar setup with double wishbone components, while the rear suspension employs a traditional leaf spring design. This combination provides a balance of ride comfort and load-carrying capacity. The braking system consists of ventilated discs on all four wheels, measuring 355×40 mm. An Anti-lock Braking System (ABS) is standard. The DRW configuration provides a wider stance and increased braking capacity compared to single-rear-wheel models. Hydraulic power steering provides responsive and precise steering control.
Market Reception & Comparison
The Silverado 3500 HD with the Duramax/Allison powertrain received generally positive reviews from automotive critics. It was praised for its powerful engine, smooth transmission, and impressive towing capabilities. Fuel economy, while typical for a heavy-duty diesel truck, was a point of consideration. Compared to the gasoline-powered Silverado 3500 HD, the Duramax diesel offered significantly better fuel economy when towing heavy loads. Against competitors like the Ford Super Duty and Ram 3500, the Silverado 3500 HD was often seen as a strong contender, offering a competitive combination of power, capability, and features.
Legacy
The Duramax L5P engine and Allison ten-speed transmission have proven to be a reliable and durable powertrain combination. While diesel engines generally require more maintenance than gasoline engines, the Duramax L5P has a reputation for longevity when properly maintained. On the used car market, Silverado 3500 HD models equipped with this powertrain hold their value well, reflecting their capability and desirability. These trucks continue to be popular choices for those needing a heavy-duty workhorse, and well-maintained examples are expected to remain on the road for many years to come.
