The GMC Sierra 3500HD IV (GMTK2XX) Crew Cab Standard Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 445 horsepower and paired with an Allison automatic transmission, represents a significant iteration in GMC’s heavy-duty truck lineage. Produced from 2017 to 2019, this variant occupied a premium position within the Sierra 3500HD lineup, targeting buyers requiring substantial towing and hauling capabilities alongside a comfortable, well-equipped cabin. It was part of the fourth generation of the Sierra/Silverado HD trucks, known as the GMTK2XX platform, which brought improvements in strength, refinement, and technology compared to its predecessors.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD IV (GMTK2XX) Crew Cab Standard Box |
| Type (Engine) | 6.6 Duramax TD V8 (445 Hp) SRW Automatic |
| Start of production | 2017 |
| End of production | 2019 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.4 kg/Hp, 135.3 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 375.1 Nm/tonne |
| Power | 445 Hp @ 2800 rpm |
| Power per litre | 67.4 Hp/l |
| Torque | 1234 Nm @ 1600 rpm (910.15 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax L5P |
| Engine displacement | 6604 cm3 (403 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103 mm (4.06 in.) |
| Piston Stroke | 99 mm (3.9 in.) |
| Compression ratio | 16:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | OHV |
| Engine oil capacity | 9.5 l (10.04 US qt | 8.36 UK qt) |
| Coolant | 29.7 l (31.38 US qt | 26.13 UK qt) |
| Kerb Weight | 3290 kg (7253.21 lbs.) |
| Max. weight | 5035 kg (11100.27 lbs.) |
| Max load | 1745 kg (3847.07 lbs.) |
| Trunk (boot) space – maximum | 1728 l (61.02 cu. ft.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 5897 kg (13000.66 lbs.) |
| Length | 6083 mm (239.49 in.) |
| Width including mirrors | 2045 mm (80.51 in.) |
| Height | 1990 mm (78.35 in.) |
| Wheelbase | 3904 mm (153.7 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Minimum turning circle (turning diameter) | 15.8 m (51.84 ft.) |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine. |
| Number of gears and type of gearbox | 6 gears, automatic transmission Allison |
| Front suspension | Coil spring, Double wishbone, Transverse stabilizer |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 360 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 235/80 R17; 265/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
INTRODUCTION
The 2017-2019 GMC Sierra 3500HD Crew Cab with the 6.6L Duramax diesel and Allison automatic transmission was a cornerstone of GMC’s heavy-duty truck offerings. Built on the GMTK2XX platform, it represented a move towards increased capability, refinement, and technology. The Crew Cab configuration provided ample passenger space, making it suitable for both work and family use, while the standard box offered a practical cargo bed length. This particular configuration was positioned as a premium offering, appealing to customers who needed a powerful and capable truck without sacrificing comfort or convenience.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD lies the Duramax L5P 6.6-liter turbocharged diesel V8. This engine is a testament to diesel engineering, featuring a cast iron block, aluminum cylinder heads, and a robust rotating assembly. The L5P utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. The turbocharger, coupled with an intercooler, provides increased air intake, boosting power and torque. The engine’s overhead valve (OHV) valvetrain, while traditional, is known for its durability and reliability. The Allison 1000 series six-speed automatic transmission is specifically designed to handle the immense torque output of the Duramax engine. This transmission features electronically controlled shifts and a lock-up torque converter for improved fuel efficiency and responsiveness. The Allison’s robust construction ensures long-term durability even under demanding conditions.
Driving Characteristics
The combination of the 445 horsepower and 910 lb-ft of torque delivered by the Duramax engine and Allison transmission results in impressive performance. While not designed for outright speed, this Sierra 3500HD excels at towing and hauling heavy loads. The Allison transmission’s gear ratios are optimized for both pulling power and highway cruising. Compared to the gasoline-powered versions of the Sierra 3500HD, the diesel offers significantly more low-end torque, making it easier to accelerate with a loaded trailer. Compared to other diesel trims, like those with slightly less power, this 445hp version offered a noticeable improvement in acceleration and overall responsiveness. The ride quality, while typical of a heavy-duty truck, is reasonably comfortable, especially in the Crew Cab configuration.
Equipment & Trim Levels
The Sierra 3500HD Crew Cab with the Duramax engine typically came well-equipped, even in its base trim. Standard features included air conditioning, power windows and locks, a rearview camera, and a basic infotainment system. Higher trim levels, such as 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 wheels, and various towing packages. The interior design focused on functionality and durability, with comfortable seating and intuitive controls.
Chassis & Braking
The Sierra 3500HD’s chassis is built for strength and durability. It features a fully boxed frame constructed from high-strength steel. The front suspension utilizes coil springs and a double wishbone design, while the rear suspension employs leaf springs. This configuration provides a good balance of ride comfort and load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing heavy loads. An Anti-lock Braking System (ABS) is standard. The rear axle was typically a single rear wheel (SRW) configuration, though dual rear wheel (DRW) options were available for even greater towing capacity.
Market Reception & Comparison
The GMC Sierra 3500HD with the Duramax diesel and Allison automatic received generally positive reviews from critics. It was praised for its powerful engine, smooth transmission, and comfortable ride. Fuel economy, while not exceptional, was considered reasonable for a heavy-duty truck. Compared to the Ford Super Duty and Ram 3500, the Sierra 3500HD was often seen as offering a more refined interior and a quieter cabin. The Duramax engine’s reputation for reliability also contributed to its appeal. However, the higher price tag compared to gasoline-powered models was a potential drawback for some buyers.
Legacy
The Duramax L5P engine and Allison transmission pairing has proven to be exceptionally reliable. Well-maintained examples of the 2017-2019 Sierra 3500HD continue to command strong resale values in the used car market. The engine is known for its longevity, with many units exceeding 200,000 miles without major issues. The Allison transmission is equally durable, capable of handling years of heavy use. This combination remains a popular choice for buyers seeking a capable and dependable heavy-duty truck, solidifying its place as a significant chapter in GMC’s truck history.
