The GMC Sierra 2500HD III, specifically the Crew Cab Long Box configuration with the 6.0-liter V8 engine producing 360 horsepower and paired with a four-wheel drive system and automatic transmission, was a prominent offering in the heavy-duty pickup truck segment from 2007 to 2010. This generation (GMT900) represented a significant step forward for GMC in terms of capability, refinement, and interior space, aiming to compete directly with offerings from Ford and Dodge. The 6.0L V8/Automatic combination occupied a sweet spot in the lineup, providing a balance of power and usability for both work and personal use.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD III (GMT900) Crew Cab Long 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 | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.7 kg/Hp, 129.3 Hp/tonne |
| Weight-to-torque ratio | 5.4 kg/Nm, 184.9 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 | 2785 kg, 6139.87 lbs. |
| Max. weight | 4173 kg, 9199.89 lbs. |
| Max load | 1388 kg, 3060.02 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%) | 5488 kg, 12098.97 lbs. |
| Length | 6572 mm, 258.74 in. |
| Width including mirrors | 2436 mm, 95.91 in. |
| Height | 1930 mm, 75.98 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 | 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 GMC Sierra 2500HD III, produced from 2007 to 2010, represented the third generation of the heavy-duty Sierra line. Built on the GMT900 platform, this truck was designed to offer increased towing capacity, payload, and interior comfort compared to its predecessors. The Crew Cab configuration, with its four full-size doors and spacious rear seating, was particularly popular with families and those needing to transport passengers alongside work-related materials. The 6.0-liter V8 engine, coupled with a four-wheel drive system and automatic transmission, was a common choice for buyers seeking a balance between capability and everyday drivability. This variant positioned itself as a versatile option, suitable for both demanding jobs and comfortable daily commuting.
Powertrain & Engine Architecture
At the heart of this Sierra 2500HD variant lies the Vortec LY6 6.0-liter V8 engine. This engine is a member of the Vortec family, known for its robust construction and relatively simple design. The LY6 features a cast iron block and aluminum cylinder heads, contributing to its durability. It utilizes a multi-port fuel injection system, delivering fuel directly to each cylinder for efficient combustion. The engine employs an overhead valve (OHV) valvetrain, a traditional design that prioritizes simplicity and reliability. The 9.6:1 compression ratio strikes a balance between power and fuel efficiency. The Hydra-Matic 4L80-E four-speed automatic transmission was the standard pairing for this engine. This transmission is known for its durability and ability to handle high torque loads, making it well-suited for heavy-duty truck applications. The 4L80-E features electronically controlled shifting for smoother operation and optimized performance.
Driving Characteristics
The 6.0-liter V8, producing 360 horsepower and 380 lb-ft of torque, provided ample power for towing and hauling, but it wasn’t the quickest configuration available. Compared to the available 8.1-liter V8 or the Duramax diesel engine, the 6.0L felt less powerful, especially when fully loaded. However, the automatic transmission offered smooth and predictable shifts, making it easy to drive in various conditions. The four-speed transmission, while reliable, lacked the efficiency and responsiveness of newer transmissions with more gears. Acceleration was adequate for everyday driving, but passing maneuvers required planning, particularly when towing. The four-wheel drive system provided excellent traction in slippery conditions, enhancing stability and control. The overall driving experience was characterized by a comfortable ride, thanks to the torsion bar front suspension and leaf spring rear suspension, although the ride could become somewhat bouncy when the truck was unloaded.
Equipment & Trim Levels
The Sierra 2500HD III in this configuration typically came standard with features such as air conditioning, power windows and locks, and a basic audio system. The Crew Cab configuration offered a spacious interior with seating for five passengers. Upholstery was typically cloth, with leather options available as upgrades. Higher trim levels, such as the SLT, added features like leather upholstery, heated seats, a premium audio system, and chrome exterior trim. Optional extras included a navigation system, a sunroof, and various towing packages. The dashboard layout was functional and straightforward, with easy-to-read gauges and intuitive controls.
Chassis & Braking
The GMT900 chassis featured a fully boxed frame for increased strength and rigidity. The front suspension utilized an independent torsion bar setup with double wishbone components, providing a comfortable ride and good handling. The rear suspension employed a traditional leaf spring design, which was well-suited for carrying heavy loads. Brakes consisted of ventilated discs on all four wheels, providing ample stopping power. The front brakes measured 325x38mm, while the rear brakes were slightly smaller at 325x30mm. An anti-lock braking system (ABS) was standard, enhancing safety and control during emergency braking situations.
Market Reception & Comparison
The GMC Sierra 2500HD III with the 6.0-liter V8 and automatic transmission was generally well-received by critics and consumers. It was praised for its comfortable ride, spacious interior, and ample towing capacity. However, some reviewers noted that the 6.0-liter engine lacked the power and efficiency of the diesel option. Fuel economy was typical for a heavy-duty pickup truck, averaging around 14-16 mpg in combined driving. Compared to the 8.1-liter V8, the 6.0L offered better fuel economy and slightly quicker acceleration. Compared to the Duramax diesel, the 6.0L was less expensive to purchase but offered significantly less torque and fuel efficiency. The 6.0L/Automatic combination appealed to buyers who prioritized affordability and usability over outright power and fuel economy.
Legacy
The Vortec LY6 6.0-liter V8 engine has proven to be a relatively reliable powertrain, with many examples still on the road today. While not without its potential issues (such as Active Fuel Management problems in some years), the engine is generally considered durable and relatively easy to maintain. The 4L80-E transmission is also known for its longevity. In the used car market, these Sierra 2500HDs represent a good value for buyers seeking a capable and affordable heavy-duty pickup truck. However, potential buyers should be aware of the engine’s potential issues and perform a thorough inspection before purchasing. The GMT900 generation Sierra 2500HD, particularly the 6.0L V8 variant, remains a popular choice for those needing a robust and reliable work truck.
