The GMC Sierra 2500HD III, specifically the Extended Cab Long Box configuration equipped with the 6.0-liter V8 engine and automatic transmission, represents a notable evolution in GMC’s heavy-duty truck lineage. Produced from 2011 to 2014 as part of the GMT900 platform’s refresh, this variant aimed to strike a balance between substantial capability and everyday usability. It occupied a key position within the Sierra 2500HD lineup, offering a significant increase in towing and payload capacity compared to the 1500 series, while remaining a more accessible option than the diesel-powered 2500HD and 3500HD models. This truck was primarily marketed to American consumers who required a powerful workhorse for both commercial and personal applications, such as hauling equipment, boats, or trailers.
Technical Specifications
| Brand | GMC |
| Model | Sierra 2500HD |
| Generation | Sierra 2500HD III (GMT900, facelift 2011) Extended Cab Long Box |
| Type (Engine) | 6.0 V8 (360 Hp) Automatic |
| Start of production | 2011 |
| End of production | 2014 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.7 kg/Hp, 129.2 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 L96 |
| 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, VVT |
| 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 | 2786 kg, 6142.08 lbs. |
| Max. weight | 4309 kg, 9499.72 lbs. |
| Max load | 1523 kg, 3357.64 lbs. |
| Trunk (boot) space – maximum | 2138 l, 75.5 cu. ft. |
| Fuel tank capacity | 136 l, 35.93 US gal | 29.92 UK gal |
| Permitted trailer load with brakes (12%) | 5897 kg, 13000.66 lbs. |
| Length | 6337 mm, 249.49 in. |
| Width including mirrors | 2032 mm, 80 in. |
| Height | 1971 mm, 77.6 in. |
| Wheelbase | 4018 mm, 158.19 in. |
| Front track | 1748 mm, 68.82 in. |
| Rear (Back) track | 1709 mm, 67.28 in. |
| Ride height (ground clearance) | 216 mm, 8.5 in. |
| Minimum turning circle (turning diameter) | 15.8 m, 51.84 ft. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| 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, 350×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 245/75 R17; 265/70 R17; 265/70 R18; 265/60 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The core of this Sierra 2500HD variant is the Vortec L96 6.0-liter V8 engine. This engine, part of GM’s Vortec family, features a cast-iron block and an overhead valve (OHV) design, renowned for its durability and straightforward construction. The L96 boasts a 9.6:1 compression ratio and utilizes multi-port fuel injection to generate 360 horsepower at 5400 rpm and 515 Nm (379.84 lb-ft) of torque at 4200 rpm. Variable valve timing (VVT) was incorporated to enhance efficiency and low-end torque delivery. The engine’s longitudinal mounting and rear-wheel-drive configuration are standard for American heavy-duty trucks. Complementing the L96 is the Hydra-Matic 6L80E six-speed automatic transmission. This transmission was selected for its robustness and ability to manage the engine’s substantial torque output. The 6L80E incorporates electronically controlled shifting and overdrive for improved fuel economy during highway driving.
Driving Characteristics
The combination of the 6.0L V8 and 6-speed automatic in the Sierra 2500HD offered a noticeable performance improvement over the available 4.8L V8. While not as swift as the optional Duramax diesel, the 6.0L provided a more responsive and familiar driving experience for drivers accustomed to gasoline engines. The automatic transmission’s gear ratios were optimized for towing and hauling, prioritizing low-end torque over rapid acceleration. In practical driving scenarios, this translated to confident acceleration when unladen, but a more measured pace when heavily loaded. Compared to manual transmission models, the automatic offered convenience, particularly in stop-and-go traffic or when navigating challenging terrain. However, it did result in some loss of driver control and potentially a slight reduction in fuel efficiency.
Equipment & Trim Levels
The 2011-2014 Sierra 2500HD with the 6.0L V8 and automatic transmission was typically available in Work Truck (WT), SLE, and SLT trim levels. The WT trim served as the base model, emphasizing functionality and affordability, with standard features including air conditioning, a basic audio system, and vinyl upholstery. The SLE trim added enhancements such as cloth upholstery, power windows and locks, and an upgraded audio system. The SLT trim represented the premium offering, featuring leather upholstery, heated seats, a premium audio system, and additional chrome exterior accents. Optional extras included a navigation system, a rear-seat entertainment system, and various towing packages.
Chassis & Braking
The Sierra 2500HD’s chassis was engineered for heavy-duty applications. It featured a fully boxed frame to increase rigidity and durability. The front suspension utilized an independent torsion bar and double wishbone setup, while the rear suspension employed a conventional leaf spring configuration. This setup delivered a comfortable ride, even when carrying substantial loads. Braking was provided by ventilated discs on all four wheels, with ABS (Anti-lock Braking System) as a standard safety feature. The front brakes measured 350x40mm, while the rear brakes were slightly smaller at 360x34mm. The braking system was appropriately sized for the truck’s weight and intended use.
Market Reception & Comparison
Industry critics generally lauded the GMC Sierra 2500HD’s overall capability and comfortable ride quality. The 6.0L V8 engine was considered a reasonable compromise between power and fuel economy, although it couldn’t match the fuel efficiency of the Duramax diesel. Compared to the diesel, the 6.0L was often perceived as more affordable to purchase and maintain, but it lacked the diesel’s superior towing capacity and fuel economy. The automatic transmission was well-received for its smooth shifting and ease of operation. However, some reviewers pointed out that the interior materials, particularly in the WT trim, felt somewhat basic compared to competing models.
Legacy
The GMT900-generation Sierra 2500HD, including the 6.0L V8 automatic variant, has demonstrated relatively good reliability in the used car market. The Vortec L96 engine is known for its longevity, and the 6L80E transmission is generally considered a durable unit. Routine maintenance requirements include regular oil changes, transmission fluid flushes, and inspections of the suspension and braking components. While not as highly sought-after as the diesel models, the 6.0L V8 Sierra 2500HD remains a popular choice for buyers seeking a capable and affordable heavy-duty truck. Its combination of power, practicality, and relative simplicity continues to appeal to a broad spectrum of customers.
