The Chevrolet Silverado 3500 HD III (K2XX) Double Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower and paired with a 4WD SRW Automatic transmission, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2017 to 2019, this variant occupied a premium position within the Silverado 3500 HD lineup, targeting buyers requiring substantial towing and hauling capabilities without sacrificing everyday usability. It was part of the third generation (K2XX platform) of the Silverado/Sierra HD trucks, known for their increased strength, refined interiors, and advanced technology compared to previous generations.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD III (K2XX) Double Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) 4WD SRW Automatic |
| Start of production | 2017 |
| End of production | 2019 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.7 kg/Hp, 130.1 Hp/tonne |
| Weight-to-torque ratio | 2.8 kg/Nm, 360.8 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 | 29.7 l (31.38 US qt | 26.13 UK qt) |
| Kerb Weight | 3420 kg (7539.81 lbs.) |
| Max. weight | 5262 kg (11600.72 lbs.) |
| Max load | 1842 kg (4060.91 lbs.) |
| Trunk (boot) space – maximum | 2162 l (76.35 cu. ft.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 6577 kg (14499.8 lbs.) |
| Length | 6321 mm (248.86 in.) |
| Width including mirrors | 2045 mm (80.51 in.) |
| Height | 1980 mm (77.95 in.) |
| Wheelbase | 4017 mm (158.15 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Minimum turning circle (turning diameter) | 16.2 m (53.15 ft.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| Number of gears and type of gearbox | 6 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, 373×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 235/80 R17; 265/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
Powertrain & Engine Architecture
The heart of this Silverado 3500 HD variant is the Duramax L5P 6.6-liter turbocharged diesel V8 engine. This engine represents a significant evolution of the Duramax design, incorporating technologies like a variable geometry turbocharger (VGT) and a high-pressure common rail fuel injection system. The L5P produces 445 horsepower at 2800 rpm and a massive 910 lb-ft (1234 Nm) of torque at 1600 rpm. The engine features a cast iron block and aluminum cylinder heads, contributing to its durability. The OHV valvetrain, while traditional, is optimized for low-end torque. The Allison 1000 six-speed automatic transmission is specifically calibrated to handle the engine’s substantial output. This transmission is known for its robustness and smooth shifting, crucial for heavy-duty applications. The 4WD system utilizes an electronically controlled transfer case, allowing the driver to switch between 2WD, 4WD High, and 4WD Low depending on road conditions.
Driving Characteristics
The 6.6L Duramax with the Allison automatic delivers a driving experience focused on capability rather than outright speed. While 445 hp is substantial, the engine’s strength lies in its immense low-end torque. This translates to effortless towing and hauling, even with heavy loads. The Allison transmission’s gear ratios are optimized for maximizing torque multiplication, allowing the truck to accelerate confidently even when fully loaded. Compared to the gasoline-powered Silverado 3500 HD models, the diesel offers significantly more torque and better fuel economy when towing. Compared to other Duramax variants, the 445 hp version provides a noticeable power increase over earlier iterations, improving acceleration and overall responsiveness. The automatic transmission, while convenient, may not offer the same level of control as a manual transmission for experienced drivers.
Equipment & Trim Levels
The Silverado 3500 HD Double Cab Long Box with the Duramax engine typically came in higher trim levels, such as LTZ or High Country. Standard features included air conditioning, power windows and locks, a premium audio system, and a rearview camera. Higher trims added features like leather upholstery, heated and ventilated front seats, a navigation system, and advanced safety technologies. Optional extras included a sunroof, upgraded wheels, and various towing packages. The Double Cab configuration provided comfortable seating for five passengers, making it suitable for both work and family use. The Long Box bed offered ample cargo space for hauling materials or equipment.
Chassis & Braking
The K2XX platform 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 wishbone control arms, while the rear suspension employs a traditional leaf spring design. This combination provides a balance of ride comfort and 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 fully floating design, capable of handling substantial loads.
Market Reception & Comparison
The Silverado 3500 HD with the Duramax engine and Allison transmission was generally well-received by critics and consumers alike. It was praised for its powerful engine, smooth transmission, and comfortable ride. Fuel economy, while not exceptional, was considered competitive for a heavy-duty truck. Compared to the Ford Super Duty and Ram HD trucks, the Silverado 3500 HD offered a compelling combination of capability, refinement, and value. The Duramax engine’s reputation for reliability and longevity also contributed to its popularity. However, some critics noted that the interior design was not as modern or luxurious as some competitors.
Legacy
The Duramax L5P engine paired with the Allison transmission has proven to be a durable and reliable powertrain. These trucks continue to hold their value in the used car market, particularly those that have been well-maintained. The L5P engine is known for its ability to withstand high mileage and heavy use. While some maintenance items, such as diesel particulate filter (DPF) regeneration, require attention, the overall cost of ownership is generally reasonable. The Silverado 3500 HD III (K2XX) remains a popular choice for those seeking a capable and dependable heavy-duty truck.
