The Chevrolet Silverado 2500 HD II, specifically the Crew Cab Long 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 through 2010 (GMT900 platform), this variant was aimed at buyers needing substantial towing and hauling capacity without sacrificing interior space and comfort. It occupied a sweet spot in the 2500HD lineup, offering a balance between the more economical gasoline engines and the higher-output Duramax variants available in later years. This model catered to owners who frequently towed large trailers – boats, RVs, or construction equipment – and required a robust, reliable powertrain.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD II (GMT900) Crew Cab Long 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 | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8.2 kg/Hp, 122.5 Hp/tonne |
| Weight-to-torque ratio | 3.3 kg/Nm, 300.3 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 | 2980 kg (6569.78 lbs.) |
| Max. weight | 4173 kg (9199.89 lbs.) |
| Max load | 1193 kg (2630.11 lbs.) |
| Trunk (boot) space – maximum | 2138 l (75.5 cu. ft.) |
| Fuel tank capacity | 129 l (34.08 US gal | 28.38 UK gal) |
| Permitted trailer load with brakes (12%) | 5897 kg (13000.66 lbs.) |
| Length | 6572 mm (258.74 in.) |
| Width including mirrors | 2032 mm (80 in.) |
| Height | 1949 mm (76.73 in.) |
| Wheelbase | 4242 mm (167.01 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) | 16.8 m (55.12 ft.) |
| Drivetrain Architecture | 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, 325×38 mm |
| Rear brakes | Ventilated discs, 325×30 mm |
| Tires size | 245/75 R16; 265/75 R17 |
| Wheel rims size | 6.5J x 16; 7.5J x 17 |
Powertrain & Engine Architecture
The heart of this Silverado 2500 HD is the Duramax LMM 6.6-liter V8 diesel engine. This engine represented a refinement of the previous LBZ Duramax, incorporating a more robust crankshaft, redesigned pistons, and improved cooling systems. The LMM utilized a common-rail fuel injection system, delivering fuel at extremely high pressures for optimized combustion and reduced emissions. The turbocharger, coupled with an intercooler, provided increased air intake, boosting power and torque. The engine’s overhead valve (OHV) configuration, while traditional, proved durable and reliable. The Allison 1000 six-speed automatic transmission was specifically designed to handle the substantial torque output of the Duramax engine. This transmission featured a lock-up torque converter for improved fuel efficiency at highway speeds and heavy-duty internal components for longevity.
Driving Characteristics
The 365 horsepower and 895 lb-ft of torque delivered by the LMM Duramax and Allison transmission combination provided impressive performance for a heavy-duty truck. While not as quick as gasoline-powered counterparts, the Silverado 2500 HD excelled in towing and hauling. The Allison transmission’s gear ratios were optimized for pulling power, allowing the truck to maintain speed even when loaded. Compared to the 1.8L gasoline engine options, the Duramax offered significantly more low-end torque, making it ideal for challenging terrain and heavy loads. The automatic transmission, while convenient, did result in a slight reduction in fuel economy compared to the available manual transmission. However, the convenience and ease of use were often preferred by owners who frequently operated the truck in stop-and-go traffic or for long-distance towing.
Equipment & Trim Levels
The Crew Cab Long Box configuration offered a spacious interior with seating for five passengers. Standard features typically included air conditioning, power windows and locks, a CD player, and cloth upholstery. The Silverado 2500 HD II offered various trim levels, with the LT and LTZ being the most common. LT models added features like chrome exterior trim, upgraded interior materials, and a premium sound system. LTZ models further enhanced the luxury with leather upholstery, heated seats, and additional convenience features. Optional extras included a navigation system, a sunroof, and a rear-seat entertainment system.
Chassis & Braking
The Silverado 2500 HD II featured a robust chassis designed to withstand heavy loads. The front suspension utilized an independent torsion bar setup with double wishbones, providing a comfortable ride while maintaining stability. 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, enhancing safety during emergency braking situations. The rear axle ratios varied depending on the specific configuration, influencing both towing capacity and fuel economy.
Market Reception & Comparison
The 2007-2010 Chevrolet Silverado 2500 HD with the 6.6L Duramax and Allison automatic received generally positive reviews. Critics praised its powerful engine, smooth-shifting transmission, and comfortable ride. Compared to the gasoline-powered Silverado 2500 HD models, the Duramax variant offered superior towing capacity and fuel economy, especially when hauling heavy loads. However, the Duramax engine carried a higher price tag. Compared to Ford’s Super Duty and Ram’s heavy-duty trucks, the Silverado 2500 HD was often considered to be competitive in terms of performance, features, and reliability.
Legacy
The Duramax LMM engine and Allison transmission pairing proved to be exceptionally durable and reliable. Properly maintained examples of the 2007-2010 Silverado 2500 HD continue to be highly sought after in the used truck market. The LMM Duramax is known for its longevity and relatively low maintenance costs compared to some later Duramax iterations. While the particulate filter system could require occasional maintenance, the overall powertrain has earned a reputation for dependability. These trucks remain a popular choice for owners who need a capable and reliable heavy-duty workhorse.
