The Chevrolet Silverado 3500 HD II (GMT900) Regular Cab Long Box, equipped with the 6.6-liter Duramax Turbo Diesel V8 engine producing 365 horsepower and paired with a 4WD SRW Automatic transmission, was a key offering in Chevrolet’s heavy-duty truck lineup from 2007 to 2010. This configuration represented a robust work truck option, positioned between the lighter-duty Silverado 2500HD and the more specialized configurations of the 3500HD line. It was designed to meet the demands of owners requiring substantial towing and hauling capabilities, particularly in the agricultural, construction, and commercial sectors.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD II (GMT900) Regular Cab Long Box |
| Type (Engine) | 6.6 Duramax TD V8 (365 Hp) 4WD SRW Automatic |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8 kg/Hp, 125.8 Hp/tonne |
| Weight-to-torque ratio | 3.2 kg/Nm, 308.4 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 | 2902 kg (6397.81 lbs.) |
| Max. weight | 4490 kg (9898.76 lbs.) |
| Max load | 1588 kg (3500.94 lbs.) |
| Trunk (boot) space – maximum | 2170 l (76.63 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 | 5714 mm (224.96 in.) |
| Width including mirrors | 2436 mm (95.91 in.) |
| Height | 1919 mm (75.55 in.) |
| Wheelbase | 3378 mm (132.99 in.) |
| Front track | 1742 mm (68.58 in.) |
| Rear (Back) track | 1676 mm (65.98 in.) |
| Ride height (ground clearance) | 233 mm (9.17 in.) |
| Minimum turning circle (turning diameter) | 13.8 m (45.28 ft.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| 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 | 265/75 R16; 225/75 R17 |
| Wheel rims size | 7J x 16; 7.5J x 17 |
Powertrain & Engine Architecture
The heart of this Silverado 3500HD variant is the Duramax LMM 6.6-liter turbocharged diesel V8. This engine, a product of Isuzu and General Motors collaboration, represented a significant upgrade over its predecessor, the LBZ. The LMM featured a redesigned combustion chamber and improved fuel injection system, contributing to increased power and reduced emissions. The common-rail fuel injection system, capable of extremely high injection pressures, ensured efficient fuel atomization and complete combustion. The engine utilized an overhead valve (OHV) valvetrain, a design choice favored for its durability and simplicity. A BorgWarner variable geometry turbocharger with an intercooler further enhanced performance. The Allison 1000 six-speed automatic transmission was specifically designed to handle the high 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 reliability under demanding conditions.
Driving Characteristics
The 365 horsepower and 895 lb-ft of torque delivered by the Duramax engine and Allison transmission combination provided substantial pulling power. While not as quick accelerating as gasoline-powered trucks, the Silverado 3500HD excelled in towing and hauling. The automatic transmission, while smooth, was tuned for durability and work-oriented performance rather than sporty responsiveness. Gear ratios were optimized for maximizing torque at lower engine speeds, making it ideal for climbing hills or pulling heavy loads. Compared to the 2500HD models with smaller engines, the 3500HD offered a significantly more confident and capable experience when towing near its maximum capacity. Compared to higher-output Duramax variants, this configuration prioritized fuel economy and longevity over outright performance.
Equipment & Trim Levels
The Silverado 3500HD II Regular Cab Long Box with the Duramax engine typically came in work truck (WT) and LT trim levels. The WT trim was fairly basic, focusing on functionality with features like vinyl upholstery, manual windows and locks, and a basic audio system. The LT trim added more comfort and convenience features, such as cloth upholstery, power windows and locks, cruise control, and an upgraded audio system. Optional extras included a trailer brake controller, navigation system, leather upholstery, and various towing packages. The regular cab configuration was geared towards commercial users and those prioritizing maximum cargo space, while the long box provided ample bed length for hauling large items.
Chassis & Braking
The Silverado 3500HD 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, known for its durability and load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power even when towing. An Anti-lock Braking System (ABS) was standard. The heavy-duty frame and suspension components contributed to the truck’s high gross vehicle weight rating (GVWR) and permitted trailer load.
Market Reception & Comparison
The Duramax-equipped Silverado 3500HD was generally well-received by critics and consumers alike. It was praised for its powerful engine, robust construction, and impressive towing capabilities. Fuel economy, while not exceptional, was considered reasonable for a heavy-duty diesel truck. Compared to Ford’s Super Duty and Dodge’s Ram trucks, the Silverado 3500HD offered a competitive combination of power, reliability, and value. The automatic transmission was often cited as a strong point, providing smooth and reliable operation. However, some reviewers noted that the interior, particularly in the WT trim, was somewhat spartan compared to its competitors.
Legacy
The GMT900 Silverado 3500HD, particularly the Duramax/Allison combination, has proven to be a durable and reliable truck. The LMM Duramax engine, while having some known issues with injector failure, is generally considered a robust powerplant when properly maintained. Today, these trucks are still commonly found in use, often with high mileage. The availability of aftermarket parts and a strong community of enthusiasts contribute to their continued viability. The 2007-2010 Silverado 3500HD represents a sweet spot for many buyers seeking a capable and affordable heavy-duty truck, offering a balance of power, reliability, and value in the used market.
