The GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Standard Box, equipped with the 6.0-liter V8 engine producing 301 horsepower and paired with a 4WD automatic transmission, and capable of running on Compressed Natural Gas (CNG), was a heavy-duty pickup truck produced by General Motors for the 2015 and 2016 model years. This variant occupied a middle ground within the Sierra 2500HD lineup, offering a balance between capability, comfort, and alternative fuel options. It was part of the fourth generation of the Sierra HD series, known as the GMTK2XX platform, which represented a significant update in terms of design, technology, and overall refinement compared to its predecessors.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD IV (GMTK2XX) Crew Cab Standard Box |
| Type (Engine) | 6.0 V8 (301 Hp) 4WD 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 |
| Permitted trailer load with brakes (12%) | 3992 kg / 8800.85 lbs. |
| Length | 6083 mm / 239.49 in. |
| Width including mirrors | 2045 mm / 80.51 in. |
| Height | 1987 mm / 78.23 in. |
| Wheelbase | 3904 mm / 153.7 in. |
| Front track | 1748 mm / 68.82 in. |
| Rear (Back) track | 1709 mm / 67.28 in. |
| Ride height (ground clearance) | 208 mm / 8.19 in. |
| Minimum turning circle (turning diameter) | 15.7 m / 51.51 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 Hydra-Matic |
| Front suspension | Coil spring, Double wishbone, Transverse stabilizer |
| 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 |
INTRODUCTION
The 2015-2016 GMC Sierra 2500HD Crew Cab with the 6.0L V8 and 4WD automatic transmission represented a workhorse option for buyers needing substantial towing and hauling capacity. Positioned within the Sierra 2500HD range, it sat above the base diesel models in terms of initial cost but offered a gasoline-powered alternative with readily available power. The addition of CNG capability broadened its appeal to fleet and environmentally conscious buyers. Built on the GMTK2XX platform, this generation of Sierra HD trucks aimed to deliver a more refined driving experience alongside traditional heavy-duty durability.
Powertrain & Engine Architecture
At the heart of this Sierra 2500HD variant lies the Vortec LC8 6.0-liter V8 engine. This engine is a member of GM’s small-block V8 family, known for its robust construction and relatively simple design. It features a cast iron block and aluminum cylinder heads. The LC8 utilizes a multi-port fuel injection system, delivering fuel directly into the intake ports. The engine employs an overhead valve (OHV) valvetrain with variable valve timing (VVT) on the intake side, enhancing low-end torque and improving fuel efficiency. The 6L90 six-speed automatic transmission, a Hydra-Matic unit, was the sole transmission option. This transmission is known for its durability and smooth shifting characteristics, and its gear ratios were optimized for both towing and everyday driving. The CNG system is a bi-fuel setup, allowing the truck to run on either gasoline or compressed natural gas, or a combination of both.
Driving Characteristics
The 6.0L V8, producing 301 horsepower and 360 lb-ft of torque, provided ample power for most heavy-duty tasks. While not as fuel-efficient as the Duramax diesel options, it offered a more familiar driving experience for those accustomed to gasoline engines. The 6L90 automatic transmission contributed to smooth acceleration and manageable gear changes. Compared to the diesel variants, this gasoline-powered Sierra 2500HD felt more responsive at higher RPMs, but lacked the low-end grunt of the diesel for extremely heavy towing. The 4WD system provided enhanced traction in challenging conditions, making it suitable for both work and recreational use. The gear ratios in the 6L90 were well-suited for towing, providing sufficient leverage to move substantial loads without excessive engine strain.
Equipment & Trim Levels
The Crew Cab configuration offered spacious seating for five passengers, making it a comfortable option for both work crews and families. Standard features typically included air conditioning, power windows and locks, a basic audio system, and a rearview camera. Higher trim levels, such as the SLE and SLT, added features like leather upholstery, heated seats, a premium audio system, and advanced safety technologies. The CNG-equipped models often came with specific badging and instrumentation to indicate their alternative fuel capability. Optional extras included a navigation system, a sunroof, and various towing packages.
Chassis & Braking
The Sierra 2500HD featured a fully boxed frame for enhanced rigidity and durability. The front suspension utilized a coil spring, double wishbone design with a transverse stabilizer bar, providing a comfortable ride and stable handling. The rear suspension employed a traditional leaf spring setup, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing heavy loads. An Anti-lock Braking System (ABS) was standard equipment, enhancing safety and control during emergency braking situations.
Market Reception & Comparison
Critics generally praised the GMC Sierra 2500HD for its robust construction, comfortable interior, and capable powertrain. The 6.0L V8/automatic combination was viewed as a solid choice for buyers who didn’t require the ultimate towing capacity of the diesel models. Fuel economy was a common criticism, as the gasoline engine consumed significantly more fuel than the diesel alternatives. However, the lower initial cost of the gasoline engine and the availability of CNG capability made it an attractive option for certain buyers. Compared to competitors like the Ford Super Duty and Ram 2500, the Sierra 2500HD offered a competitive blend of features, performance, and value.
Legacy
The 6.0L Vortec LC8 engine, paired with the 6L90 transmission, has proven to be a relatively reliable powertrain combination. While not immune to age-related issues, these components are generally known for their durability and longevity. In the used car market, these Sierra 2500HD models remain popular choices for buyers seeking a capable and affordable heavy-duty truck. The CNG-equipped variants are particularly sought after by those looking to reduce their fuel costs and environmental impact. Regular maintenance, including oil changes and fluid checks, is crucial for ensuring the continued reliability of these trucks.
