The Chevrolet Silverado 3500 HD III (K2XX) Double Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 397 horsepower and paired with a 4WD SRW Automatic transmission, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2015 to 2017, 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, known for its increased strength and improved ride quality compared to its predecessors.
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 (397 Hp) 4WD SRW Automatic |
| Start of production | 2015 |
| End of production | 2017 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8.5 kg/Hp, 117.8 Hp/tonne |
| Weight-to-torque ratio | 3.3 kg/Nm, 307.6 Nm/tonne |
| Power | 397 Hp @ 3000 rpm |
| Power per litre | 60.2 Hp/l |
| Torque | 1037 Nm @ 1600 rpm, 764.85 lb.-ft. @ 1600 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax LML |
| Engine displacement | 6599 cm3, 402.7 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 | 22.4 l, 23.67 US qt | 19.71 UK qt |
| Kerb Weight | 3371 kg, 7431.78 lbs |
| Max. weight | 5262 kg, 11600.72 lbs |
| Max load | 1891 kg, 4168.94 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 |
| Ride height (ground clearance) | 223 mm, 8.78 in |
| Minimum turning circle (turning diameter) | 16.2 m, 53.15 ft |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| 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 |
INTRODUCTION
The 2015-2017 Chevrolet Silverado 3500 HD Double Cab Long Box with the 6.6L Duramax diesel and Allison automatic transmission was a workhorse designed for serious tasks. Positioned as a premium offering within the Silverado 3500 HD range, it catered to customers needing substantial towing and payload capacity without sacrificing everyday usability. Built on the K2XX platform, this generation represented a move towards increased strength, improved refinement, and enhanced technology compared to previous Silverado HD models. The Double Cab configuration offered a balance between passenger space and bed length, making it suitable for both work and family needs.
Powertrain & Engine Architecture
At the heart of this Silverado 3500 HD variant lies the Duramax LML 6.6-liter turbocharged diesel V8 engine. This engine is a testament to diesel engineering, featuring a cast iron block, aluminum cylinder heads, and a robust rotating assembly. The LML Duramax utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion and efficiency. The turbocharger, coupled with an intercooler, provides increased air intake, boosting power and torque. The engine’s valvetrain employs an overhead valve (OHV) configuration, known for its simplicity and durability.
The Allison 1000 Series 6-speed automatic transmission is specifically engineered to handle the immense torque output of the Duramax engine. This transmission features a lock-up torque converter for improved fuel efficiency and a heavy-duty design for reliability under demanding conditions. The Allison transmission’s gear ratios are optimized for both towing and everyday driving, providing a balance between power delivery and fuel economy. The transmission is electronically controlled, allowing for smooth and precise shifting.
Driving Characteristics
The Silverado 3500 HD 6.6L Duramax with the Allison automatic delivers a driving experience characterized by substantial power and torque. The 397 horsepower and 765 lb-ft of torque are readily available, making it capable of effortlessly towing heavy loads and navigating challenging terrain. While not as quick off the line as gasoline-powered trucks, the Duramax provides a broad and flat torque curve, resulting in strong acceleration across a wide range of speeds. The Allison transmission shifts smoothly and efficiently, contributing to a comfortable driving experience even when heavily loaded. Compared to the 6.0L gasoline V8 option, the Duramax offers significantly more torque, making it the preferred choice for serious towing. Compared to manual transmission equipped Duramax models, the automatic provides ease of use, particularly in stop-and-go traffic, but may sacrifice a small degree of fuel efficiency.
Equipment & Trim Levels
The Silverado 3500 HD Double Cab Long Box with the Duramax engine typically came well-equipped, even in its base trim levels. Standard features included air conditioning, power windows and locks, a tilt steering wheel, and a basic audio system. Higher trim levels, such as the LT and High Country, added features like leather upholstery, heated and ventilated front seats, a premium audio system, navigation, and advanced safety technologies. Optional extras included a sunroof, rear-seat entertainment system, and various towing packages. The Double Cab configuration offered comfortable seating for five passengers, with ample legroom and headroom. Interior materials were generally durable and practical, reflecting the truck’s work-oriented nature.
Chassis & Braking
The K2XX platform chassis of the Silverado 3500 HD is designed for strength and durability. 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 design, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing heavy loads. An Anti-lock Braking System (ABS) is standard, enhancing safety and control. The truck’s robust frame and heavy-duty suspension components contribute to its impressive towing and payload capabilities.
Market Reception & Comparison
The Silverado 3500 HD with the Duramax diesel engine 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 considered reasonable for a heavy-duty truck of its size and capability. Compared to the Ford Super Duty and Ram 3500, the Silverado 3500 HD offered a competitive combination of performance, features, and value. The Duramax engine was often cited as a key selling point, offering a compelling alternative to the gasoline-powered options. Reliability was generally good, although some owners reported issues with the diesel particulate filter (DPF) system.
Legacy
The Duramax LML engine and Allison transmission pairing in the 2015-2017 Silverado 3500 HD 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 LML Duramax is known for its longevity and relatively low maintenance costs, making it a popular choice among truck buyers. While newer Silverado HD models offer more advanced technology and features, the K2XX generation remains a capable and dependable workhorse, representing a sweet spot for buyers seeking a proven heavy-duty truck at a reasonable price.
