The Chevrolet Silverado 2500HD II, specifically the facelifted version produced from 2011 to 2014, represented a significant evolution of Chevrolet’s heavy-duty truck lineup. This iteration, designated GMT900, continued the Silverado’s tradition of providing robust capability and durability for demanding tasks. Within the 2500HD range, the Extended Cab Standard Box configuration with the 6.6-liter Duramax Turbo Diesel V8 engine paired with an Allison automatic transmission occupied a sweet spot, offering a balance of power, practicality, and towing capacity for both commercial and personal use. This variant was positioned as a workhorse, appealing to buyers needing substantial payload and towing abilities without the added length of a crew cab.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD II (GMT900, facelift 2011) Extended Cab Standard Box |
| Type (Engine) | 6.6 Duramax TD V8 (397 Hp) 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 | 7.8 kg/Hp, 127.9 Hp/tonne |
| Weight-to-torque ratio | 3 kg/Nm, 334 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 | 3105 kg (6845.35 lbs.) |
| Max. weight | 4536 kg (10000.17 lbs.) |
| Max load | 1431 kg (3154.81 lbs.) |
| Trunk (boot) space – maximum | 1718 l (60.67 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 | 5857 mm (230.59 in.) |
| Width including mirrors | 2032 mm (80 in.) |
| Height | 1979 mm (77.91 in.) |
| Wheelbase | 3663 mm (144.21 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Ride height (ground clearance) | 218 mm (8.58 in.) |
| Minimum turning circle (turning diameter) | 14.6 m (47.9 ft.) |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine. |
| 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, 350×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 245/75 R17; 265/70 R17; 265/70 R18; 265/60 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Silverado 2500HD variant is the 6.6-liter Duramax LML turbo diesel V8 engine. This engine represented a significant upgrade over its predecessor, the LBZ, with improvements focused on emissions compliance and increased durability. The LML utilizes a cast iron block and aluminum cylinder heads, contributing to its robust construction. The engine employs a high-pressure common rail fuel injection system, delivering fuel at extremely high pressures for optimized combustion and efficiency. A variable geometry turbocharger (VGT) with an intercooler further enhances performance by providing increased boost across a wider RPM range. The overhead valve (OHV) valvetrain, while a more traditional design, proved reliable and well-suited for the demands of a heavy-duty truck. The Allison 1000 six-speed automatic transmission is a key component, renowned for its durability and ability to handle the engine’s substantial torque output. This transmission features a lock-up torque converter for improved fuel economy at highway speeds and is electronically controlled for smooth and precise shifting.
Driving Characteristics
The 6.6-liter Duramax in this configuration delivers a commanding driving experience. While not as overtly quick as gasoline-powered trucks, the immense 1037 Nm (764.85 lb-ft) of torque provides effortless acceleration, even when towing heavy loads. The Allison transmission is well-matched to the engine, providing smooth and predictable shifts. The gear ratios are optimized for towing and hauling, with a relatively low first gear for getting heavy loads moving. Compared to the 6.0-liter gasoline V8 offered in the Silverado 2500HD, the Duramax provides significantly more low-end torque, making it far more capable for demanding tasks. Compared to higher-output Duramax variants, this 397 hp version offers a more manageable power delivery, making it easier to control when towing. The extended cab configuration provides additional interior space compared to the regular cab models, but the standard box length offers a good balance between cargo capacity and maneuverability.
Equipment & Trim Levels
The 2011-2014 Silverado 2500HD with the Duramax/Allison combination typically came standard with a respectable level of equipment. This included air conditioning, power windows and locks, a basic audio system, and vinyl upholstery. The Extended Cab configuration added a second row of seating, although legroom was limited. Optional extras included leather upholstery, a premium audio system, navigation, a backup camera, and various towing packages. Trim levels, such as LT and LTZ, offered progressively more luxurious features and appointments. The standard steel wheels were often upgraded to alloy wheels as part of optional packages.
Chassis & Braking
The Silverado 2500HD II utilizes a body-on-frame construction, providing a robust and durable platform. The front suspension features an independent torsion bar setup with double wishbones, offering a comfortable ride and good handling. The rear suspension employs a traditional leaf spring design, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. An Anti-lock Braking System (ABS) is standard. The rear axle ratio varied depending on the specific configuration, influencing both towing capacity and fuel economy. The steering system utilizes a cone worm with recirculation balls, providing a solid and predictable feel.
Market Reception & Comparison
The 2011-2014 Silverado 2500HD with the 6.6-liter Duramax and Allison transmission was generally well-received by critics and consumers alike. It was praised for its robust towing capacity, comfortable ride, and durable powertrain. Fuel economy, while not exceptional, was considered reasonable for a heavy-duty truck. Compared to the Ford Super Duty and Ram 2500/3500, the Silverado offered a competitive combination of features and performance. The Duramax/Allison combination was often cited as a key advantage, offering a smooth and reliable powertrain. However, some critics noted that the interior design was somewhat dated compared to its competitors.
Legacy
The Duramax LML engine and Allison transmission pairing in the Silverado 2500HD II have proven to be exceptionally durable and reliable. These trucks continue to be highly sought after in the used car market, particularly by those needing a capable and dependable work truck. Properly maintained examples can easily exceed 200,000 miles with minimal issues. The LML Duramax is known for its relatively clean emissions system compared to later iterations, making it a popular choice for those seeking a reliable and relatively easy-to-maintain diesel engine. The Silverado 2500HD II with this powertrain remains a testament to Chevrolet’s commitment to building tough and capable trucks.
