The Chevrolet Silverado 3500 HD III (K2XX) Crew Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower and paired with an Allison 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 alongside a degree of comfort and refinement. It was part of the third generation of the K2XX platform, a chassis designed specifically for heavy-duty truck applications, and played a crucial role in Chevrolet’s ongoing competition with Ford and Ram in the North American full-size truck market.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD III (K2XX) Crew Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) 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 | 7.5 kg/Hp, 132.9 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 368.6 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 | 3348 kg (7381.08 lbs.) |
| Max. weight | 5171 kg (11400.1 lbs.) |
| Max load | 1823 kg (4019.03 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 | 6563 mm (258.39 in.) |
| Width including mirrors | 2045 mm (80.51 in.) |
| Height | 1979 mm (77.91 in.) |
| Wheelbase | 4259 mm (167.68 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Minimum turning circle (turning diameter) | 17.1 m (56.1 ft.) |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine (ICE) drives the rear wheels. |
| 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. This engine represents a significant evolution of the Duramax design, incorporating a cast iron block, aluminum cylinder heads, and a robust rotating assembly. The L5P utilizes a diesel commonrail fuel injection system, delivering highly pressurized fuel directly into the cylinders for optimized combustion. The engine produces 445 horsepower at 2800 rpm and a massive 910 lb-ft (1234 Nm) of torque at 1600 rpm. The overhead valve (OHV) valvetrain, while seemingly traditional, is engineered for durability and low-end torque production. The Allison 1000 Series six-speed automatic transmission is specifically calibrated to handle the engine’s substantial output. This transmission is known for its durability and smooth shifting characteristics, crucial for heavy-duty applications. The transmission features a lock-up torque converter to improve fuel efficiency at highway speeds.
Driving Characteristics
The 6.6L Duramax with the Allison automatic delivers a driving experience focused on capability rather than outright speed. While not a sports truck, the abundant torque provides effortless acceleration, even when towing heavy loads. The Allison transmission’s programming prioritizes smooth, confident shifts, minimizing gear hunting. Compared to the gasoline-powered Silverado 3500 HD models, the diesel offers significantly more low-end grunt, making it ideal for hauling and towing. Compared to the 6.0L gasoline V8, the Duramax provides a much flatter torque curve, meaning consistent power delivery across a wider RPM range. The automatic transmission, while convenient, doesn’t offer the same level of control as a manual transmission, but it excels in providing a relaxed driving experience, especially in stop-and-go traffic.
Equipment & Trim Levels
The Silverado 3500 HD III Crew Cab Long Box 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, air conditioning, power windows and locks, and a basic infotainment system. Higher trims added features like leather upholstery, heated and ventilated front seats, a premium sound system, navigation, and advanced safety technologies. Optional extras included a sunroof, upgraded wheels, and various towing packages. The Long Box configuration provided ample bed space for hauling cargo, making it a versatile work truck.
Chassis & Braking
The K2XX chassis is a fully boxed frame designed for strength and rigidity. The front suspension utilizes an independent torsion bar setup with double wishbones, providing a comfortable ride and good handling. The rear suspension employs a traditional leaf spring setup, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes at all four corners, providing ample stopping power even when heavily loaded. The front brakes measure 355x40mm, while the rear brakes are 373x34mm. An Anti-lock Braking System (ABS) is standard equipment. The steering system utilizes a cone worm with recirculation balls, offering a solid and predictable feel.
Market Reception & Comparison
The Duramax-equipped Silverado 3500 HD was generally well-received by critics and consumers alike. It was praised for its powerful engine, smooth transmission, and impressive towing capacity. Fuel economy, while not exceptional, was competitive for a heavy-duty diesel truck. Compared to the gasoline-powered Silverado 3500 HD, the Duramax offered superior towing performance and better fuel economy when hauling heavy loads. However, the Duramax engine and Allison transmission came at a significant price premium. Reliability was generally good, although some owners reported issues with the diesel particulate filter (DPF) system, a common concern with modern diesel engines.
Legacy
The 2017-2019 Silverado 3500 HD with the 6.6L Duramax and Allison automatic remains a popular choice in the used truck market. The L5P Duramax engine is known for its durability and longevity, and the Allison transmission is widely regarded as one of the most reliable automatic transmissions available. These trucks continue to command a premium price compared to their gasoline-powered counterparts, reflecting their capability and reputation for reliability. The K2XX platform proved to be a robust and capable foundation for Chevrolet’s heavy-duty trucks, setting the stage for future generations.
