The GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Standard Box with the 6.0L V8 engine and automatic transmission, offered between 2015 and 2016, represented a significant offering in the heavy-duty pickup truck segment. This variant, notable for its optional Compressed Natural Gas (CNG) capability, was positioned as a workhorse for those needing substantial towing and payload capacity, while also offering an alternative fuel option. It sat within the fourth generation of the Sierra 2500HD, built on the GMTK2XX platform, alongside other engine options like the Duramax diesel. This particular configuration aimed to balance power, capability, and a degree of fuel efficiency through the use of CNG.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD IV (GMTK2XX) Crew 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 |
| 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 | 1988 mm / 78.27 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) | 213 mm / 8.39 in. |
| Minimum turning circle (turning diameter) | 15.7 m / 51.51 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 | 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 6.0-liter V8 and automatic transmission was a key component of GMC’s heavy-duty truck lineup. Built on the GMTK2XX platform, this generation Sierra aimed to provide a balance of rugged capability and refined comfort. The availability of a CNG option distinguished this variant, appealing to fleet operators and individuals seeking to reduce their reliance on gasoline. The Crew Cab configuration offered increased passenger space, making it suitable for both work and family use. This model year represented a transitional period for the Sierra 2500HD, bridging the gap between older designs and the more technologically advanced models that followed.
Powertrain & Engine Architecture
At the heart of this Sierra 2500HD lay the Vortec LC8 6.0-liter V8 engine. This engine, a staple in GM’s truck lineup for years, is a naturally aspirated, overhead valve (OHV) design featuring variable valve timing (VVT). The LC8 utilized multi-port fuel injection to deliver fuel to the cylinders. The engine produced 301 horsepower at 5000 rpm and 360 lb-ft of torque at 4200 rpm. The engine’s robust construction and relatively simple design contributed to its reputation for reliability. The 6L80E six-speed automatic transmission, a Hydra-Matic unit, was the sole transmission offering for this configuration. This transmission was known for its durability and smooth shifting characteristics, providing adequate gear ratios for both towing and everyday driving. The CNG system, when equipped, allowed the truck to run on either gasoline or compressed natural gas, or a combination of both, offering flexibility and potentially lower fuel costs depending on CNG prices.
Driving Characteristics
The 6.0L V8 and 6L80E automatic combination delivered a capable, if not particularly sporty, driving experience. Acceleration was adequate for a heavy-duty truck, but the focus was clearly on towing and hauling. The automatic transmission provided smooth shifts, and the gear ratios were well-suited for maintaining momentum when towing heavy loads. Compared to the available Duramax diesel engine, the 6.0L V8 offered less torque and lower fuel economy, but it was significantly less expensive to purchase and maintain. The CNG option, when utilized, slightly reduced horsepower and torque output compared to gasoline operation, but offered the benefit of lower emissions and potentially lower fuel costs. The truck’s substantial weight and rear-wheel-drive configuration meant that it wasn’t particularly nimble in corners, but the suspension provided a reasonably comfortable ride, even when unladen.
Equipment & Trim Levels
The Sierra 2500HD offered a range of trim levels, with the base model providing essential features and higher trims adding more luxury and convenience items. Standard equipment on this variant typically included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. The Crew Cab configuration provided ample space for five passengers. Optional extras included leather upholstery, a premium audio system, navigation, a rearview camera, and various towing packages. The CNG-equipped models often came with specific gauges and controls related to the alternative fuel system. The interior design was functional and durable, prioritizing practicality over outright luxury.
Chassis & Braking
The Sierra 2500HD’s chassis was designed to withstand the stresses of heavy-duty use. It featured a fully boxed frame and a robust suspension system. The front suspension utilized coil springs and a double wishbone design, while the rear suspension employed leaf springs. This configuration provided a good balance of ride comfort and load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels. An Anti-lock Braking System (ABS) was standard, enhancing safety and control during emergency braking situations. The rear axle ratio varied depending on the specific configuration, influencing both towing capacity and fuel economy.
Market Reception & Comparison
The GMC Sierra 2500HD with the 6.0L V8 and automatic transmission was generally well-received by critics and consumers. It was praised for its robust construction, comfortable ride, and ample interior space. However, the 6.0L V8 was often criticized for its relatively low fuel economy compared to the Duramax diesel engine. The CNG option was seen as a positive feature, particularly for fleet operators looking to reduce their environmental impact and fuel costs. Compared to competitors like the Ford Super Duty and Ram 2500, the Sierra 2500HD offered a competitive combination of features, capability, and value.
Legacy
The 2015-2016 GMC Sierra 2500HD with the 6.0L V8 and automatic transmission remains a popular choice in the used truck market. The Vortec LC8 engine is known for its reliability, and the 6L80E transmission is also considered to be durable. However, potential buyers should be aware of potential issues such as oil consumption and Active Fuel Management (AFM) system failures. The CNG-equipped models require specialized maintenance and may have limited refueling infrastructure availability. Overall, this Sierra 2500HD variant represents a capable and dependable heavy-duty truck that continues to provide value to owners today.
