2015-2019 GMC Sierra 3500HD IV (GMTK2XX) Crew Cab Long Box 6.0 V8 (360 Hp) 4WD SRW Automatic

The GMC Sierra 3500HD IV (GMTK2XX) Crew Cab Long Box, equipped with the 6.0-liter V8 engine producing 360 horsepower and paired with a four-wheel-drive system and automatic transmission, represents a significant iteration in GMC’s heavy-duty truck lineage. Produced from 2015 to 2019, this variant occupied a sweet spot in the Sierra 3500HD lineup, offering a balance of capability, comfort, and technology aimed at buyers needing serious towing and hauling capacity without the expense of the diesel options. It was part of the fourth generation of the Sierra/Silverado HD trucks, known internally as the GMTK2XX platform, which brought substantial improvements in interior refinement, ride quality, and available features.

Technical Specifications

INTRODUCTION

The 2015-2019 GMC Sierra 3500HD Crew Cab Long Box with the 6.0L V8 and automatic transmission was positioned as a robust, gasoline-powered alternative to the increasingly popular Duramax diesel offerings. It catered to owners who prioritized initial cost savings and the simplicity of gasoline engine maintenance over the higher torque and fuel economy of a diesel. The “GMTK2XX” designation refers to the truck’s platform, which was a significant redesign over the previous generation, focusing on improved interior space, ride comfort, and overall refinement. The Crew Cab configuration offered ample passenger space, while the Long Box provided a generous cargo bed for hauling. This particular trim level was generally considered a mid-range offering, often serving as a base for buyers who then added optional packages to customize their truck.

Powertrain & Engine Architecture

At the heart of this Sierra 3500HD variant lies the Vortec L96 6.0-liter V8 engine. This engine is a member of GM’s Vortec family, known for its robust construction and relatively simple design. It features a cast iron block and aluminum cylinder heads, utilizing a 9.6:1 compression ratio and a naturally aspirated intake. The L96 employs multi-port fuel injection, delivering fuel directly to each cylinder. The valvetrain utilizes an overhead valve (OHV) configuration with variable valve timing (VVT) to optimize performance and efficiency across the engine’s operating range. The engine produces 360 horsepower at 5400 rpm and 380 lb-ft of torque at 4200 rpm.

The engine is mated to a six-speed automatic transmission (likely the 6L90E), designed to handle the substantial torque output of the V8. This transmission features electronically controlled shifting and overdrive for improved fuel economy at highway speeds. The 4WD system is a traditional part-time system, allowing the driver to switch between two-wheel drive and four-wheel drive as needed.

Driving Characteristics

The 6.0L V8/automatic combination in the Sierra 3500HD delivers adequate, but not overwhelming, performance. Acceleration is respectable for a heavy-duty truck, but it doesn’t offer the immediate responsiveness of the diesel options. The automatic transmission generally shifts smoothly, but can sometimes feel hesitant when downshifting for passing maneuvers. The gear ratios are tuned for towing and hauling, prioritizing low-end torque over outright speed. Compared to the 6.6L Duramax diesel, the 6.0L V8 lacks the sheer pulling power, especially when heavily loaded. However, the gasoline engine is quieter and smoother in operation, and doesn’t suffer from the diesel particulate filter issues common in modern diesel engines.

Equipment & Trim Levels

The standard equipment on the 2015-2019 Sierra 3500HD with the 6.0L V8 typically included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. The Crew Cab configuration provided generous space for five passengers. Higher trim levels, such as the SLE and SLT, added features like leather upholstery, heated seats, a premium audio system, navigation, and a rearview camera. Optional extras included a trailer brake controller, a gooseneck hitch, and various appearance packages.

Chassis & Braking

The Sierra 3500HD features a heavy-duty chassis designed to withstand the stresses of towing and hauling. The front suspension utilizes coil springs and a double wishbone design, while the rear suspension employs a traditional leaf spring setup. Brakes are ventilated discs on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) is standard. The rear axle ratio varied depending on the specific configuration, influencing both towing capacity and fuel economy.

Market Reception & Comparison

Critics generally praised the Sierra 3500HD for its comfortable ride, spacious interior, and robust construction. However, the 6.0L V8 engine was often seen as a compromise compared to the more powerful and fuel-efficient Duramax diesel. Fuel economy was a common complaint, with the gasoline engine delivering significantly lower MPG than the diesel. Reliability was generally good, but the 6.0L V8 was known to be susceptible to Active Fuel Management (AFM) issues, where the engine deactivated cylinders to save fuel, potentially leading to oil consumption and other problems. The diesel models commanded a higher price but offered superior towing capacity and fuel economy, making them the preferred choice for many heavy-duty truck buyers.

Legacy

The GMC Sierra 3500HD IV (GMTK2XX) with the 6.0L V8 remains a popular choice in the used truck market, particularly for buyers seeking a capable and affordable heavy-duty truck. While the diesel models hold their value better, the 6.0L V8 offers a lower entry price and simpler maintenance. The engine’s long-term reliability is generally good, provided that it has been properly maintained and any AFM issues have been addressed. These trucks continue to be used for a variety of tasks, including towing boats and trailers, hauling materials, and general work truck duties.