The Chevrolet Silverado 2500 HD II, specifically the Extended Cab Standard Box configuration powered by the 6.6-liter Duramax turbodiesel V8 engine paired with an Allison automatic transmission, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2007 to 2010 (GMT900 platform), this variant occupied a sweet spot in the lineup, offering a compelling blend of towing capacity, diesel efficiency, and everyday usability for owners needing a robust work truck. It was positioned as a step up from the gasoline-powered engines, targeting buyers who frequently hauled heavy loads or required the durability and longevity associated with a diesel powertrain.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD II (GMT900) Extended Cab Standard Box |
| Type (Engine) | 6.6 Duramax TD V8 (365 Hp) Automatic |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.8 kg/Hp, 128 Hp/tonne |
| Weight-to-torque ratio | 3.2 kg/Nm, 313.9 Nm/tonne |
| Power | 365 Hp @ 3200 rpm |
| Power per litre | 55.3 Hp/l |
| Torque | 895 Nm @ 1600 rpm (660.12 lb.-ft. @ 1600 rpm) |
| Maximum engine speed | 3450 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax LMM |
| 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 | 16.8:1 |
| 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 | 2851 kg (6285.38 lbs.) |
| Max. weight | 4173 kg (9199.89 lbs.) |
| Max load | 1322 kg (2914.51 lbs.) |
| Trunk (boot) space – maximum | 1718 l (60.67 cu. ft.) |
| Fuel tank capacity | 98 l (25.89 US gal | 21.56 UK gal) |
| Permitted trailer load with brakes (12%) | 5897 kg (13000.66 lbs.) |
| Length | 5850 mm (230.31 in.) |
| Width including mirrors | 2032 mm (80 in.) |
| Height | 1951 mm (76.81 in.) |
| Wheelbase | 3645 mm (143.5 in.) |
| Front track | 1744 mm (68.66 in.) |
| Rear (Back) track | 1676 mm (65.98 in.) |
| Ride height (ground clearance) | 243 mm (9.57 in.) |
| Minimum turning circle (turning diameter) | 14.5 m (47.57 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, 325×38 mm |
| Rear brakes | Ventilated discs, 325×30 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 245/75 R16; 265/75 R17 |
| Wheel rims size | 6.5J x 16; 7.5J x 17 |
Powertrain & Engine Architecture
At the heart of this Silverado 2500 HD II lies the Duramax LMM 6.6-liter V8 diesel engine. This engine represented a significant evolution of the Duramax platform, incorporating a redesigned combustion chamber and a more efficient turbocharger system. The LMM featured a common-rail fuel injection system, delivering highly pressurized fuel directly into the cylinders for improved combustion and reduced emissions. The engine produced 365 horsepower at 3200 rpm and a robust 895 lb-ft of torque at 1600 rpm. This torque output was particularly crucial for heavy towing and hauling applications. The engine utilized an overhead valve (OHV) valvetrain, a design choice favored for its durability and simplicity. The Allison 1000 six-speed automatic transmission was specifically engineered to handle the immense torque output of the Duramax engine. This transmission was known for its robustness and smooth shifting characteristics, contributing to a comfortable driving experience even under heavy loads.
Driving Characteristics
The 6.6L Duramax with the Allison automatic provided a markedly different driving experience compared to the gasoline-powered Silverado 2500 HD models. While not as quick off the line as its gasoline counterparts, the diesel offered a broad, flat torque curve that made hauling and towing effortless. The Allison transmission’s gear ratios were optimized for maximizing torque delivery, allowing the truck to maintain speed on inclines and navigate challenging terrain with ease. Compared to manual transmission equipped Duramax models, the automatic offered greater convenience, particularly in stop-and-go traffic. However, some drivers preferred the greater control offered by a manual gearbox. The overall driving experience was characterized by a sense of solidity and capability, reflecting the truck’s heavy-duty construction and powerful powertrain.
Equipment & Trim Levels
The Silverado 2500 HD II with the Duramax/Allison combination typically came in LT or Work Truck trim levels. The Work Truck trim was more basic, focusing on functionality and affordability, with features like vinyl upholstery, manual windows and locks, and a basic audio system. The LT trim offered a more refined interior, including cloth upholstery, power windows and locks, cruise control, and an upgraded audio system. Optional extras included leather upholstery, a navigation system, a premium Bose audio system, and various towing packages. Extended Cab models provided additional rear seating and storage space, enhancing the truck’s versatility.
Chassis & Braking
The Silverado 2500 HD II featured a robust chassis designed to withstand the stresses of heavy-duty use. 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, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, with ABS (Anti-lock Braking System) as standard equipment. The rear brakes were slightly smaller in diameter than the front brakes. The truck’s heavy weight and robust braking system provided ample stopping power, even when towing heavy loads.
Market Reception & Comparison
The 2007-2010 Silverado 2500 HD with the Duramax/Allison combination was generally well-received by critics and consumers alike. It was praised for its powerful engine, smooth-shifting transmission, and impressive towing capacity. Fuel economy, while not exceptional, was considered reasonable for a heavy-duty truck of its size and capability. Compared to the gasoline-powered Silverado 2500 HD models, the Duramax diesel offered significantly better fuel economy and a longer engine lifespan. Compared to competing trucks from Ford and Ram, the Silverado 2500 HD was often seen as a strong contender, offering a compelling combination of performance, reliability, and value.
Legacy
The Duramax LMM engine and Allison transmission pairing in the Silverado 2500 HD II have proven to be remarkably durable and reliable. These trucks continue to be popular in the used car market, commanding relatively high prices due to their reputation for longevity and capability. While some maintenance items, such as the fuel injectors and turbocharger, may require attention after extended use, the overall powertrain is known for its robustness. The 2007-2010 Silverado 2500 HD remains a popular choice for owners who need a dependable and capable heavy-duty truck for work or recreational purposes.
