2017-2019 GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Standard Box 6.6 TD V8 (445 Hp) Automatic

Technical Specifications

The 2017-2019 GMC Sierra 2500HD Crew Cab equipped with the 6.6-liter Duramax turbo-diesel V8 engine and paired with an Allison automatic transmission, represented a high-capability offering within GMC’s heavy-duty truck lineup. Produced as part of the fourth-generation Sierra 2500HD series (GMTK2XX platform), this variant catered to buyers needing substantial towing and hauling capacity alongside a degree of comfort and refinement. It was a key vehicle in the North American market, where heavy-duty trucks are frequently used for both commercial and personal applications.

Powertrain & Engine Architecture

The core of this Sierra 2500HD is the Duramax L5P 6.6-liter turbocharged diesel V8. This engine showcases advanced diesel technology, featuring a cast iron block for durability, aluminum cylinder heads to reduce weight, and a robust internal rotating assembly. The L5P employs a Bosch common rail fuel injection system, delivering fuel at extremely high pressures to optimize combustion efficiency and power output. A turbocharger, working in conjunction with an intercooler, increases air density, further enhancing performance. The engine generates 445 horsepower at 2800 rpm and a substantial 910 lb-ft (1234 Nm) of torque at 1600 rpm. The Allison 1000 Series six-speed automatic transmission is engineered to handle the immense torque produced by the Duramax. This transmission is renowned for its durability and smooth shifting, contributing to a more refined driving experience despite the truck’s considerable size and weight. It features electronically controlled shifting and a lock-up torque converter to improve fuel economy.

Driving Characteristics

The pairing of the high-output Duramax diesel and the Allison automatic transmission delivers impressive performance characteristics. While not focused on outright speed, the Sierra 2500HD excels in towing and hauling applications. The 910 lb-ft of torque provides effortless acceleration, even when heavily loaded. The Allison transmission’s gear ratios are carefully calibrated for both strong low-end torque and comfortable highway cruising. Compared to gasoline-powered Sierra 2500HD models, the diesel offers significantly more torque, making it far more capable for demanding tasks. Compared to diesel trims equipped with manual transmissions, the automatic provides a more relaxed driving experience, particularly in congested traffic. However, some drivers might prefer the more direct control offered by a manual gearbox. The truck’s substantial weight and heavy-duty suspension result in a firm ride quality, but the Crew Cab configuration provides a more comfortable interior compared to standard cab models.

Equipment & Trim Levels

The 2017-2019 GMC Sierra 2500HD IV (GMTK2XX) Crew Cab Standard Box 6.6 TD V8 (445 Hp) Automatic typically included standard features such as air conditioning, power windows and locks, a basic infotainment system, and a rearview camera. Higher trim levels, like the SLT and Denali, added features like leather upholstery, heated and ventilated seats, a premium sound system, navigation, and advanced safety technologies. Optional extras included a sunroof, upgraded wheel designs, and various towing packages tailored to specific needs. The interior design prioritized functionality and durability, providing a comfortable and practical environment for both the driver and passengers.

Chassis & Braking

The Sierra 2500HD boasts a robust chassis designed to withstand substantial loads. The front suspension utilizes coil springs and a double wishbone setup, while the rear suspension employs leaf springs. This configuration strikes a balance between ride comfort and load-carrying capacity. Braking is provided by ventilated disc brakes on all four wheels, offering ample stopping power. An Anti-lock Braking System (ABS) is standard equipment. The truck’s steering system employs a cone worm with recirculation balls, delivering a solid and predictable steering feel. Standard tire sizes varied depending on the trim level and wheel size, ranging from 235/80 R17 to 265/60 R20.

Market Reception & Comparison

The GMC Sierra 2500HD with the Duramax diesel and Allison automatic was generally well-received by both automotive critics and consumers. It was praised for its powerful engine, smooth transmission, and impressive towing capabilities. Fuel economy, while not exceptional for a vehicle of this size, was considered reasonable for a heavy-duty truck. Compared to the gasoline-powered Sierra 2500HD, the diesel variant offered significantly improved fuel economy when towing heavy loads. Reliability was generally good, although diesel engines can sometimes be more expensive to maintain than gasoline engines due to the complexity of the fuel injection system and emissions control components. The Sierra 2500HD directly competed with the Ford Super Duty and Ram 2500/3500 series trucks.

Legacy

The Duramax L5P engine and Allison transmission pairing has proven to be exceptionally durable and reliable. These trucks continue to hold their value in the used car market, particularly those that have been meticulously maintained. The L5P Duramax is known for its longevity and ability to accumulate high mileage. While modern diesel engines are facing increased scrutiny regarding emissions regulations, the 2017-2019 Sierra 2500HD remains a popular choice for those seeking a capable and dependable heavy-duty truck. The combination of power, reliability, and a comfortable interior has solidified its reputation as a respected workhorse in the North American truck market.