2015-2016 GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Long Box 6.0 V8 (301 Hp) 4WD Automatic CNG

The GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Long Box, specifically 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 significant position within the Sierra 2500HD lineup, offering a balance between capability, comfort, and alternative fuel options. It represented GMC’s commitment to providing robust work trucks with increasing efficiency and environmental considerations, appealing to both commercial users and individual truck enthusiasts.

Technical Specifications

INTRODUCTION

The 2015-2016 GMC Sierra 2500HD Crew Cab Long Box with the 6.0L V8 and 4WD automatic transmission represented a workhorse offering in GMC’s heavy-duty truck lineup. Built on the GMTK2XX platform, this generation of Sierra 2500HD trucks aimed to provide increased strength, refinement, and capability compared to its predecessors. The addition of CNG capability on this specific variant broadened its appeal to fleets and individuals seeking alternative fuel options. This configuration was positioned as a mid-range offering, providing a substantial step up in capability from the base 6.0L models while remaining more accessible than the more expensive Duramax diesel options.

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 Vortec family, known for its robust construction and reliable performance. The LC8 features a cast iron block and aluminum cylinder heads, utilizing a 9.6:1 compression ratio and a multi-port fuel injection system. The engine employs an overhead valve (OHV) valvetrain with variable valve timing (VVT) to optimize performance and efficiency. The 301 horsepower and 333.38 lb-ft of torque are delivered at 5000 and 4200 rpm respectively. The engine is longitudinally mounted in the chassis. The powertrain is completed by the Hydra-Matic 6L90 six-speed automatic transmission, known for its durability and smooth shifting. This transmission was specifically tuned to handle the high torque output of the 6.0L V8 and provide adequate gearing 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/automatic combination in the Sierra 2500HD delivered a capable, if not particularly sporty, driving experience. The 6L90 transmission provides smooth and predictable shifts, but the focus is clearly on maximizing towing capacity and hauling ability rather than acceleration. Compared to the manual transmission versions, the automatic offered greater convenience, especially in stop-and-go traffic. However, it did result in a slight reduction in fuel economy and a less direct connection to the engine. Compared to the more powerful Duramax diesel variants, the 6.0L V8 offered less low-end torque, making it less ideal for extremely heavy towing. However, it was more responsive at higher RPMs and offered a quieter, smoother driving experience. The 4WD system provided excellent traction in various conditions, making it suitable for both on-road and off-road use.

Equipment & Trim Levels

The Crew Cab Long Box configuration provided ample interior space for passengers and cargo. Standard features on this trim typically included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. Higher trim levels, such as the SLT and Denali, added features like leather upholstery, heated seats, a premium audio system, and advanced safety technologies. The CNG-equipped models often included specific gauges and indicators to monitor the CNG fuel level and system performance. Optional extras included a navigation system, a rear-seat entertainment system, and various towing packages.

Chassis & Braking

The Sierra 2500HD featured a robust chassis designed to handle heavy loads. The front suspension utilized coil springs and a double wishbone design with a transverse stabilizer bar, while the rear suspension employed a traditional leaf spring setup. This configuration provided a comfortable ride while maintaining excellent load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power. An Anti-lock Braking System (ABS) was standard equipment. The truck’s heavy-duty frame and suspension components contributed to its impressive towing and payload capabilities.

Market Reception & Comparison

The 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. The CNG option was seen as a positive step towards reducing emissions and fuel costs, although the limited availability of CNG refueling stations was a concern for some buyers. Compared to the diesel-powered models, the 6.0L V8 offered a lower initial cost but sacrificed some towing capacity and fuel efficiency. Compared to competitors like the Ford Super Duty and Ram 2500, the Sierra 2500HD offered a competitive combination of features, performance, and value.

Legacy

The 2015-2016 GMC Sierra 2500HD 6.0L V8 CNG variant remains a capable and reliable work truck in the used car market. The Vortec LC8 engine is known for its durability, and the 6L90 transmission is also generally considered to be a robust unit. While the CNG system may require periodic maintenance, it can offer significant fuel savings for owners who have access to affordable CNG fuel. These trucks continue to be popular among contractors, farmers, and individuals who need a heavy-duty pickup truck for work or recreational purposes. Their relatively affordable price point and proven reliability make them a compelling option in the used truck market.