The Chevrolet Silverado 3500 HD II, specifically the Extended Cab Long Box configuration with the 6.6-liter Duramax Turbo Diesel V8 engine paired with an Allison automatic transmission, represents a significant iteration of Chevrolet’s heavy-duty pickup truck lineage. Produced from 2011 to 2014 as part of the GMT900 platform’s facelift, this variant was aimed at buyers needing substantial towing and hauling capacity without sacrificing everyday usability. It occupied a sweet spot in the Silverado 3500 HD lineup, offering a powerful diesel option in a versatile body style, appealing to both commercial users and private owners engaged in demanding tasks.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD II (GMT900, facelift 2011) Extended Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (397 Hp) SRW Automatic |
| Start of production | 2011 |
| End of production | 2014 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.7 kg/Hp, 129.9 Hp/tonne |
| Weight-to-torque ratio | 2.9 kg/Nm, 339.2 Nm/tonne |
| Power | 397 Hp @ 3000 rpm |
| Power per litre | 60.2 Hp/l |
| Torque | 1037 Nm @ 1600 rpm (764.85 lb.-ft. @ 1600 rpm) |
| Maximum engine speed | 3000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax LML |
| Engine displacement | 6599 cm3 (402.7 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 | 24 l (25.36 US qt | 21.12 UK qt) |
| Kerb Weight | 3057 kg (6739.53 lbs.) |
| Max. weight | 5261 kg (11598.52 lbs.) |
| Max load | 2204 kg (4858.99 lbs.) |
| Trunk (boot) space – maximum | 2138 l (75.5 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 | 6337 mm (249.49 in.) |
| Width including mirrors | 2436 mm (95.91 in.) |
| Height | 1966 mm (77.4 in.) |
| Wheelbase | 4018 mm (158.19 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Ride height (ground clearance) | 221 mm (8.7 in.) |
| Minimum turning circle (turning diameter) | 15.8 m (51.84 ft.) |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission Allison |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 373×34 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 | 6.5J x 17; 8J x 18 |
Powertrain & Engine Architecture
The heart of this Silverado 3500 HD II is the Duramax LML 6.6-liter turbocharged diesel V8. This engine represented a significant evolution of the Duramax design, incorporating a redesigned combustion chamber, improved fuel injection system, and a more robust cooling system. The LML utilized a common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion efficiency and reduced emissions. The turbocharger, coupled with an intercooler, provided increased air intake, boosting power and torque output. The engine’s overhead valve (OHV) valvetrain, while traditional, was known for its durability and reliability. The Allison 6-speed automatic transmission was specifically calibrated to handle the immense torque produced by the Duramax engine. This transmission featured a lock-up torque converter for improved fuel efficiency at highway speeds and heavy-duty internal components to withstand the stresses of frequent towing and hauling.
Driving Characteristics
The 397 horsepower and 765 lb-ft of torque delivered by the Duramax/Allison combination translated into impressive real-world performance. While not a sports truck, the Silverado 3500 HD II offered strong acceleration, even when heavily loaded. The Allison transmission’s gear ratios were optimized for both towing and everyday driving, providing smooth and predictable shifts. Compared to the gasoline-powered Silverado 3500 HD models, the diesel variant offered significantly more low-end torque, making it ideal for pulling heavy trailers or navigating challenging terrain. Compared to higher-output Duramax variants, this 397 hp version offered a balance between power and fuel economy, making it a practical choice for those who didn’t require the absolute maximum towing capacity.
Equipment & Trim Levels
The Extended Cab Long Box configuration offered a spacious interior with seating for five passengers. Standard features typically included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. The Silverado 3500 HD II offered several trim levels, with the base Work Truck (WT) model being the most utilitarian. Higher trims, such as the LT and LTZ, added features like cloth or leather upholstery, upgraded audio systems, chrome exterior trim, and additional convenience features. Optional extras included a navigation system, a rear-seat entertainment system, and various towing packages.
Chassis & Braking
The Silverado 3500 HD II featured a robust chassis designed to handle heavy loads. The front suspension utilized an independent torsion bar setup with double wishbones, providing a comfortable ride and good handling characteristics. The rear suspension employed a traditional leaf spring design, offering 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 rear axle was a single rear wheel (SRW) configuration, suitable for most towing applications.
Market Reception & Comparison
The 2011-2014 Chevrolet Silverado 3500 HD II with the 6.6-liter Duramax diesel and Allison automatic transmission was generally well-received by critics and consumers alike. It was praised for its powerful engine, smooth transmission, and comfortable ride. Fuel economy, while not exceptional, was competitive for a heavy-duty pickup truck. Compared to the gasoline-powered Silverado 3500 HD models, the diesel variant offered significantly better fuel economy when towing or hauling heavy loads. Compared to Ford’s Super Duty and Ram’s heavy-duty trucks, the Silverado 3500 HD II was often seen as a strong contender, offering a compelling combination of power, capability, and value.
Legacy
The Duramax LML engine and Allison transmission pairing proved to be exceptionally durable and reliable. Well-maintained examples of the 2011-2014 Silverado 3500 HD II continue to command strong resale values in the used car market. The powertrain is known for its longevity, with many units exceeding 200,000 miles without major issues. The Silverado 3500 HD II remains a popular choice for those seeking a capable and reliable heavy-duty pickup truck, and its reputation for durability ensures its continued presence on roads and job sites for years to come.
