The GMC Sierra 2500HD III, produced between 2007 and 2010, represented GMC’s third generation of heavy-duty pickup trucks, designated by the GMT900 platform. This particular variant, the Extended Cab Standard Box configuration equipped with the 6.0-liter V8 engine producing 360 horsepower and paired with a four-speed automatic transmission and four-wheel drive, occupied a significant middle ground in the Sierra 2500HD lineup. It aimed to balance capability with a degree of everyday usability, appealing to buyers needing substantial towing and hauling capacity without the bulk of a crew cab.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD III (GMT900) Extended Cab Standard Box |
| Type (Engine) | 6.0 V8 (360 Hp) 4WD Automatic |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.4 kg/Hp, 135.9 Hp/tonne |
| Weight-to-torque ratio | 5.1 kg/Nm, 194.4 Nm/tonne |
| Power | 360 Hp @ 5400 rpm |
| Power per litre | 60.3 Hp/l |
| Torque | 515 Nm @ 4200 rpm, 379.84 lb.-ft. @ 4200 rpm |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Vortec LY6 |
| Engine displacement | 5967 cm3, 364.13 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 101.6 mm, 4 in. |
| Piston Stroke | 92 mm, 3.62 in. |
| Compression ratio | 9.6:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 5.7 l, 6.02 US qt | 5.02 UK qt |
| Coolant | 15.5 l, 16.38 US qt | 13.64 UK qt |
| Kerb Weight | 2649 kg, 5840.05 lbs. |
| Max. weight | 4173 kg, 9199.89 lbs. |
| Max load | 1524 kg, 3359.84 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%) | 5625 kg, 12401 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 | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 6 gears, automatic transmission Hydra-Matic |
| 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 |
INTRODUCTION
The 2007-2010 GMC Sierra 2500HD, built on the GMT900 platform, was a significant redesign for GMC’s heavy-duty truck line. The Extended Cab configuration offered a compromise between the regular cab’s affordability and the crew cab’s passenger space, featuring smaller rear doors and seating. The 6.0-liter Vortec LY6 V8 engine, paired with the Hydra-Matic 4L80-E four-speed automatic transmission and a four-wheel-drive system, was a popular choice for buyers needing substantial capability. This combination positioned the truck as a workhorse suitable for towing trailers, hauling heavy loads, and tackling challenging terrain, while remaining relatively accessible in price compared to the diesel options.
Powertrain & Engine Architecture
The heart of this Sierra 2500HD is the Vortec LY6 6.0-liter V8 engine. This engine is a member of GM’s Vortec family, known for its robust construction and relatively simple design. It features a cast iron block and aluminum cylinder heads. The LY6 utilizes a multi-port fuel injection system, delivering fuel directly to each cylinder intake port. The overhead valve (OHV) valvetrain, while not as technologically advanced as overhead cam designs, is known for its durability and ease of maintenance. The 4L80-E four-speed automatic transmission is a heavy-duty unit designed to handle the engine’s torque output and the demands of heavy towing. It’s a electronically controlled transmission, offering smooth shifts and reliable performance. The four-speed configuration, while adequate for the time, is less efficient than modern transmissions with more gears.
Driving Characteristics
The 6.0-liter V8 and four-speed automatic combination in the Sierra 2500HD delivered respectable, if not exhilarating, performance. With 360 horsepower and 380 lb-ft of torque, the truck was capable of accelerating adequately when unladen, but its true strength lay in its towing and hauling abilities. The 4L80-E transmission’s gear ratios were optimized for pulling power, providing strong low-end torque. However, the limited number of gears meant that engine RPMs could be relatively high at highway speeds, impacting fuel economy and potentially increasing noise levels. Compared to the available Duramax diesel engine, this gasoline V8 offered less torque and lower fuel efficiency, but it was significantly less expensive to purchase and maintain. The manual transmission options, when available, provided more direct control and potentially better fuel economy, but the automatic was favored by many for its convenience, especially when towing.
Equipment & Trim Levels
The Sierra 2500HD offered a range of trim levels, with the base model providing essential features and higher trims adding more luxury and convenience items. The 6.0-liter V8/automatic combination was available across several trims. Standard equipment typically included air conditioning, power windows and locks, and a basic audio system. Optional extras included features like leather upholstery, a premium sound system, power-adjustable seats, and a navigation system. The Extended Cab configuration featured a small rear seat, suitable for occasional passengers, and under-seat storage. The interior materials were generally durable and functional, reflecting the truck’s work-oriented nature.
Chassis & Braking
The Sierra 2500HD’s chassis was designed for heavy-duty use. It featured a robust frame and a heavy-duty suspension system. The front suspension utilized independent torsion bars and a double wishbone design, providing a comfortable ride and good handling. The rear suspension employed a traditional leaf spring setup, 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 truck’s high ground clearance and four-wheel-drive system made it capable of navigating rough terrain.
Market Reception & Comparison
The GMC Sierra 2500HD with the 6.0-liter V8 and automatic transmission was generally well-received by critics and consumers. It was praised for its strong towing and hauling capabilities, comfortable ride, and relatively affordable price. However, it was often criticized for its fuel economy, which was lower than that of comparable diesel-powered trucks. Compared to the 6.6-liter Duramax diesel engine, the 6.0-liter V8 offered less power and torque, but it was significantly cheaper to purchase and maintain. The diesel engine was favored by those who frequently towed heavy loads or drove long distances, while the gasoline V8 was a more practical choice for those who used their trucks for lighter-duty tasks.
Legacy
The GMT900-generation Sierra 2500HD, particularly the 6.0-liter V8/automatic combination, remains a popular choice in the used truck market. The Vortec LY6 engine is known for its reliability and durability, although it is susceptible to oil consumption issues if not properly maintained. The 4L80-E transmission is also generally reliable, but it may require occasional servicing. These trucks offer a good balance of capability, affordability, and durability, making them a practical choice for buyers needing a heavy-duty pickup truck. While not as fuel-efficient or technologically advanced as modern trucks, the 2007-2010 Sierra 2500HD remains a capable and dependable workhorse.
