The Chevrolet Silverado 2500HD III (K2XX) Regular Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 397 horsepower and paired with a 4WD automatic transmission, was a mainstay of Chevrolet’s heavy-duty truck lineup from 2015 to 2017. This configuration represented a work-focused variant within the broader K2XX Silverado HD range, designed for demanding tasks like towing and hauling. It occupied a position between the gasoline-powered variants and the more specialized, higher-trim diesel offerings, appealing to buyers prioritizing capability and durability over luxury features.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD III (K2XX) Regular Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (397 Hp) 4WD Automatic |
| Start of production | 2015 |
| End of production | 2017 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.9 kg/Hp, 126.4 Hp/tonne |
| Weight-to-torque ratio | 3 kg/Nm, 330.1 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 | 3141 kg (6924.72 lbs.) |
| Max. weight | 4491 kg (9900.96 lbs.) |
| Max load | 1350 kg (2976.24 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 | 5699 mm (224.37 in.) |
| Width including mirrors | 2035 mm (80.12 in.) |
| Height | 1975 mm (77.76 in.) |
| Wheelbase | 3393 mm (133.58 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Ride height (ground clearance) | 231 mm (9.09 in.) |
| Minimum turning circle (turning diameter) | 14 m (45.93 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, 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 |
INTRODUCTION
The 2015-2017 Chevrolet Silverado 2500HD with the 6.6L Duramax diesel and automatic transmission was part of the K2XX generation of Silverado and Sierra heavy-duty trucks. This generation represented a significant overhaul for GM’s heavy-duty lineup, focusing on increased capability, improved refinement, and enhanced towing performance. The Regular Cab Long Box configuration, combined with the Duramax engine, was specifically geared towards commercial users and individuals needing a robust, no-frills work truck. It was a popular choice for those requiring substantial towing capacity and the longevity associated with the Duramax diesel engine.
Powertrain & Engine Architecture
At the heart of this Silverado 2500HD variant lies the Duramax LML 6.6-liter turbocharged diesel V8. This engine is renowned for its durability and torque output. The LML iteration of the Duramax introduced several refinements over its predecessor, including a redesigned turbocharger, improved fuel injection system, and enhanced exhaust gas recirculation (EGR) system. The engine utilizes a common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. The overhead valve (OHV) valvetrain, while traditional, is known for its reliability and simplicity. The engine produces 397 horsepower at 3000 rpm and a massive 765 lb-ft (1037 Nm) of torque at 1600 rpm. This torque figure is crucial for heavy towing and hauling. The Allison 6-speed automatic transmission is specifically designed to handle the high torque output of the Duramax engine. It features a lock-up torque converter for improved fuel efficiency and a heavy-duty cooling system to prevent overheating under strenuous conditions. The transmission’s gear ratios are optimized for both towing and everyday driving, providing a balance between power and efficiency.
Driving Characteristics
The Silverado 2500HD 6.6L Duramax Automatic delivers a driving experience focused on capability rather than outright speed. While the 397 horsepower is adequate, the engine’s strength lies in its immense low-end torque. This allows for effortless towing of heavy loads and confident acceleration even with a substantial payload. Compared to the gasoline-powered Silverado 2500HD variants, the Duramax diesel offers significantly more torque, resulting in superior towing and hauling performance. However, it lacks the responsiveness of the gasoline engines. The Allison automatic transmission shifts smoothly and predictably, providing seamless power delivery. The gear ratios are well-matched to the engine’s torque curve, ensuring that the truck remains in the optimal power band during most driving situations. Compared to a manual transmission equipped Duramax, the automatic offers convenience and ease of use, particularly in stop-and-go traffic or when towing on hilly terrain.
Equipment & Trim Levels
The Regular Cab Long Box configuration typically represented the base work-truck trim level. Standard features included air conditioning, a basic audio system, vinyl upholstery, and manual windows and locks. The interior was functional and durable, prioritizing practicality over luxury. Optional extras included power windows and locks, upgraded audio systems, a trailer brake controller, and various towing packages. Higher trim levels, such as the LT and High Country, offered more luxurious features, but the base model focused on providing essential functionality at an affordable price point.
Chassis & Braking
The Silverado 2500HD features a robust chassis designed to withstand the stresses of heavy-duty use. 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, offering excellent load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels. The front brakes measure 355×40 mm, while the rear brakes are 360×34 mm. An Anti-lock Braking System (ABS) is standard, enhancing safety and control during emergency braking situations. The truck’s heavy weight and robust suspension contribute to a stable and planted feel, even when towing heavy loads.
Market Reception & Comparison
The Silverado 2500HD 6.6L Duramax Automatic was generally well-received by critics and consumers alike. It was praised for its exceptional towing and hauling capabilities, its durable powertrain, and its comfortable ride. Fuel economy, while not a primary concern for heavy-duty truck buyers, was considered acceptable for a vehicle of this size and capability. Compared to the gasoline-powered Silverado 2500HD variants, the Duramax diesel offered superior towing performance and fuel efficiency when towing heavy loads. However, it came with a higher initial cost and potentially higher maintenance expenses. Compared to competing heavy-duty trucks from Ford and Ram, the Silverado 2500HD was considered a strong contender, offering a compelling combination of capability, reliability, and value.
Legacy
The Duramax LML engine paired with the Allison automatic transmission has proven to be a remarkably reliable powertrain. Properly maintained, these engines can easily exceed 200,000 miles. On the used car market, the 2015-2017 Silverado 2500HD 6.6L Duramax Automatic remains a popular choice for buyers seeking a capable and durable work truck. Values tend to be higher than comparable gasoline-powered models, reflecting the demand for the Duramax diesel engine. The K2XX generation Silverado 2500HD established a strong reputation for reliability and capability, solidifying Chevrolet’s position as a leader in the heavy-duty truck segment.
