The Chevrolet Silverado 2500 HD III (K2XX) Double Cab Standard Box, equipped with the 6.0-liter V8 engine producing 301 horsepower and paired with an automatic transmission, and capable of running on Compressed Natural Gas (CNG), was a configuration offered for the 2015 and 2016 model years. This variant occupied a middle ground within the Silverado 2500 HD lineup, offering a balance between capability, fuel efficiency (when utilizing CNG), and cost compared to the diesel-powered options and heavier-duty configurations. It was primarily marketed towards customers needing substantial towing and hauling capacity but who didn’t require the ultimate power of the Duramax diesel.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD III (K2XX) Double Cab Standard Box |
| Type (Engine) | 6.0 V8 (301 Hp) Automatic CNG |
| Start of production | 2015 |
| End of production | 2016 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol / CNG |
| Power | 301 Hp @ 5000 rpm |
| Power per litre | 50.4 Hp/l |
| Torque | 452 Nm @ 4200 rpm / 333.38 lb.-ft. @ 4200 rpm |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Vortec LC8 |
| Engine displacement | 5967 cm3 / 364.13 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 101.6 mm / 4 in. |
| Piston Stroke | 92 mm / 3.62 in. |
| Compression ratio | 9.6:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV, VVT |
| Engine oil capacity | 5.7 l / 6.02 US qt | 5.02 UK qt |
| Coolant | 15.5 l / 16.38 US qt | 13.64 UK qt |
| Fuel tank capacity | 136 l / 35.93 US gal | 29.92 UK gal |
| CNG cylinder capacity | 67 kg |
| Length | 5841 mm / 229.96 in. |
| Width including mirrors | 2045 mm / 80.51 in. |
| Height | 1984 mm / 78.11 in. |
| Wheelbase | 3662 mm / 144.17 in. |
| Front track | 1748 mm / 68.82 in. |
| Rear (Back) track | 1709 mm / 67.28 in. |
| Ride height (ground clearance) | 218 mm / 8.58 in. |
| Minimum turning circle (turning diameter) | 15 m / 49.21 ft. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission Hydra-Matic |
| 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 2500 HD variant is the Vortec LC8 6.0-liter V8 engine. This engine, a member of Chevrolet’s small-block family, is a naturally aspirated, 90-degree V-engine featuring cast iron block and aluminum cylinder heads. It utilizes a multi-port fuel injection system for precise fuel delivery and overhead valve (OHV) valvetrain with variable valve timing (VVT) to optimize performance and efficiency. The LC8 engine is known for its robust construction and relatively simple design, contributing to its reliability. The 6L80 Hydra-Matic six-speed automatic transmission was the standard pairing for this engine. This transmission is electronically controlled and designed to handle the high torque output of the V8, offering smooth shifting and a wide gear ratio spread for both towing and everyday driving. The addition of CNG capability allowed owners to take advantage of potentially lower fuel costs and reduced emissions, although it required the installation of a dedicated CNG tank and fuel system.
Driving Characteristics
The 6.0L V8 with the 6-speed automatic provided adequate, but not exceptional, performance for a heavy-duty truck. With 301 horsepower and 360 lb-ft of torque, acceleration was sufficient for highway merging and passing, but it lacked the immediate responsiveness of the diesel options. The automatic transmission was tuned for smooth operation and towing, meaning it wasn’t as aggressive in downshifting as some performance-oriented automatics. The gear ratios were optimized for pulling loads, providing strong low-end torque. Compared to the 6.6L Duramax diesel, this gasoline engine offered significantly less towing capacity and fuel economy. However, it was quieter and smoother in operation, and the initial purchase price was lower. Compared to the 4.8L V8, the 6.0L offered a noticeable increase in power and towing capability.
Equipment & Trim Levels
The Double Cab Standard Box configuration offered a good balance of passenger space and bed length. Standard equipment typically included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. Higher trim levels, such as the LT and LTZ, added features like leather upholstery, heated seats, a premium audio system, navigation, and advanced safety features. The CNG-equipped models often came with specific badging and instrumentation to indicate their alternative fuel capability. Optional extras included a trailer brake controller, upgraded suspension packages, and various appearance packages.
Chassis & Braking
The Silverado 2500 HD III (K2XX) utilized a fully boxed frame for enhanced rigidity and durability. The front suspension featured an independent torsion bar setup with double wishbone components, providing a comfortable ride and good handling. The rear suspension employed a traditional leaf spring design, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, with ABS as standard. The rear brakes were slightly larger in diameter than the front. Steering was accomplished via a recirculating ball steering system, providing a solid and predictable feel.
Market Reception & Comparison
Critics generally viewed the 6.0L V8/automatic combination as a competent, if not outstanding, powertrain. It was praised for its reliability and relatively low maintenance costs compared to the diesel options. However, it was often criticized for its lower fuel economy and limited towing capacity. The CNG capability was seen as a positive feature for those seeking to reduce their environmental impact and fuel costs, but the limited availability of CNG refueling stations was a drawback. In terms of reliability, the LC8 engine proved to be fairly robust, although it was susceptible to oil consumption issues in some cases. Compared to the Duramax diesel, the 6.0L V8 offered a lower total cost of ownership but sacrificed performance and capability.
Legacy
The Chevrolet Silverado 2500 HD III (K2XX) with the 6.0L V8 and automatic transmission remains a popular choice in the used truck market. Its relatively simple design and proven reliability make it an attractive option for buyers seeking a capable and affordable heavy-duty truck. While the CNG-equipped models are less common, they offer a unique opportunity for those looking to utilize alternative fuels. The LC8 engine, while not as powerful or fuel-efficient as modern engines, continues to be a workhorse for many owners, and parts availability remains good. The combination of a robust powertrain, durable chassis, and comfortable cabin has ensured that this Silverado variant has maintained a solid reputation among truck enthusiasts and professionals alike.
