The Chevrolet Silverado 2500HD III (K2XX) Double Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower and paired with a 6-speed Allison automatic transmission, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2017 to 2019, this configuration occupied a premium position within the Silverado 2500HD lineup, targeting buyers requiring substantial towing and hauling capabilities without sacrificing everyday usability. It was part of the third generation of the K2XX platform, known for its increased strength and refinement compared to its predecessors.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD III (K2XX) Double Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) 4WD 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 | 7.6 kg/Hp, 132.2 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 366.7 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 | 3365 kg (7418.56 lbs.) |
| Max. weight | 4536 kg (10000.17 lbs.) |
| Max load | 1171 kg (2581.61 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 | 1977 mm (77.83 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, 350×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 245/75 R17; 265/70 R17; 265/70 R18; 265/60 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Silverado 2500HD variant is the Duramax L5P 6.6-liter turbocharged diesel V8. This engine represents a significant evolution of the Duramax design, incorporating a robust cast iron block, aluminum cylinder heads, and a sophisticated fuel injection system. The L5P utilizes a common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion and reduced emissions. The turbocharger, coupled with an intercooler, provides increased air density for enhanced power output. The engine’s OHV valvetrain, while traditional, is known for its durability and reliability. The Allison 1000 6-speed automatic transmission is specifically designed to handle the high torque output of the Duramax engine. It features electronically controlled shifts and a lock-up torque converter for improved fuel efficiency.
Driving Characteristics
The combination of the 445 horsepower Duramax engine and the Allison automatic transmission delivers a compelling driving experience. While not as overtly sporty as some gasoline-powered trucks, the Silverado 2500HD offers substantial low-end torque, making it exceptionally capable for towing and hauling heavy loads. The automatic transmission provides smooth and predictable shifts, although it may not be as quick to downshift as a manual transmission. The gear ratios are optimized for maximizing torque at lower speeds, which is crucial for work-related tasks. Compared to the 6.0L gasoline V8 option, the Duramax provides significantly more torque and better fuel economy, especially when towing. Compared to higher output Duramax variants, this version offers a balance between power and cost, making it accessible to a wider range of buyers.
Equipment & Trim Levels
The Double Cab Long Box configuration offered a spacious interior with seating for five passengers. Standard features typically included air conditioning, power windows and locks, a basic infotainment system with a touchscreen display, and a rearview camera. Higher trim levels, such as the LTZ and High Country, added features like leather upholstery, heated and ventilated front seats, a premium sound system, and advanced safety technologies. Optional extras included a sunroof, navigation system, and various towing packages. The interior design was functional and durable, prioritizing practicality over luxury.
Chassis & Braking
The Silverado 2500HD III 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 wishbone components, 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. An Anti-lock Braking System (ABS) is standard. The rear axle ratios varied depending on the specific configuration, influencing both towing capacity and fuel economy.
Market Reception & Comparison
The 2017-2019 Chevrolet Silverado 2500HD with the 6.6L Duramax and Allison automatic received generally positive reviews. Critics praised its powerful engine, smooth transmission, and impressive towing capabilities. Fuel economy, while not exceptional, was considered competitive for a heavy-duty truck. Compared to the Ford Super Duty and Ram 2500, the Silverado 2500HD was often seen as offering a good balance of performance, comfort, and value. Some reviewers noted that the interior design was less refined than its competitors, but the overall functionality and durability were well-regarded.
Legacy
The Duramax L5P engine and Allison transmission pairing have proven to be exceptionally reliable, with many examples exceeding 200,000 miles with proper maintenance. The Silverado 2500HD III remains a popular choice in the used truck market, particularly among buyers seeking a capable and dependable work truck. Regular maintenance, including oil changes and fuel filter replacements, is crucial for ensuring the longevity of the Duramax engine. The availability of aftermarket performance upgrades allows owners to further enhance the truck’s capabilities. This specific configuration continues to hold its value well, reflecting its reputation for durability and performance.
