The GMC Sierra 3500HD III, specifically the Extended Cab Long Box configuration with the 6.0-liter V8 engine and automatic transmission, was a heavy-duty pickup truck produced from 2007 to 2010. Part of the GMT900 generation, this variant occupied a significant position in GMC’s lineup, catering to buyers needing substantial towing and hauling capabilities. It represented a blend of work-truck durability and increasingly refined interior appointments, appealing to both commercial users and private owners requiring a robust vehicle. This particular model, designated as a “DRW” (Dual Rear Wheel) configuration, further enhanced its load-carrying capacity.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD III (GMT900) Extended Cab Long Box |
| Type (Engine) | 6.0 V8 (360 Hp) DRW 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 | 7.9 kg/Hp, 126.5 Hp/tonne |
| Weight-to-torque ratio | 5.5 kg/Nm, 181 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 | 2846 kg, 6274.36 lbs |
| Max. weight | 5171 kg, 11400.1 lbs |
| Max load | 2325 kg, 5125.75 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%) | 5443 kg, 11999.76 lbs |
| Length | 6330 mm, 249.21 in |
| Width including mirrors | 2436 mm, 95.91 in |
| Height | 1931 mm, 76.02 in |
| Wheelbase | 4001 mm, 157.52 in |
| Front track | 1742 mm, 68.58 in |
| Rear (Back) track | 1897 mm, 74.69 in |
| Ride height (ground clearance) | 233 mm, 9.17 in |
| 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, 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; 265/70 R17; 225/75 R17 |
| Wheel rims size | 6.5J x 17; 7J x 16; 7.5J x 17 |
INTRODUCTION
The GMC Sierra 3500HD III, in its 6.0L V8 DRW Automatic guise, was a cornerstone of GMC’s heavy-duty truck offerings from 2007 through 2010. Built on the GMT900 platform, alongside its Chevrolet Silverado 3500HD counterpart, this truck was designed for demanding tasks. The “HD” designation signifies “Heavy Duty,” indicating its increased payload and towing capacity compared to lighter-duty Sierra models. The Extended Cab configuration provided additional passenger space, while the Long Box offered a substantial cargo bed. The Dual Rear Wheel (DRW) setup was specifically aimed at customers needing maximum stability and load-carrying ability, such as those hauling large trailers or heavy equipment.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD lay the Vortec LY6 6.0-liter V8 engine. This engine, a member of GM’s Vortec family, was known for its robust construction and reliable performance. It featured a cast iron block and aluminum cylinder heads, contributing to its durability. The LY6 utilized a multi-port fuel injection system, delivering fuel directly to each cylinder for efficient combustion. The overhead valve (OHV) valvetrain, while a traditional design, proved to be dependable and relatively simple to maintain. The engine produced 360 horsepower at 5400 rpm and 515 lb-ft of torque at 4200 rpm. This power was channeled through a six-speed Hydra-Matic automatic transmission, specifically tuned for heavy-duty applications. The transmission featured electronically controlled shifting for smooth and precise gear changes, optimizing power delivery for both towing and everyday driving.
Driving Characteristics
The 6.0L V8 and six-speed automatic combination in the Sierra 3500HD delivered a driving experience focused on capability rather than outright speed. While not a performance-oriented truck, the engine provided ample torque for hauling heavy loads and navigating challenging terrain. The automatic transmission’s gear ratios were optimized for towing, providing strong acceleration from a standstill and maintaining comfortable cruising speeds even when heavily loaded. Compared to the available Duramax diesel engine option, the 6.0L V8 offered a lower initial cost but sacrificed some fuel efficiency and ultimate towing capacity. Compared to the standard cab models, the extended cab added a bit of weight, slightly impacting acceleration, but the added space was a worthwhile trade-off for many users. The DRW configuration significantly improved stability, especially when towing, but also made maneuvering in tight spaces more challenging.
Equipment & Trim Levels
The Sierra 3500HD III offered a range of trim levels, with the 6.0L V8 Automatic typically found in the SLE and SLT trims. Standard features included air conditioning, power windows and locks, and a basic audio system. The SLE trim added features like chrome exterior accents and upgraded interior materials. The SLT trim offered even more luxury, including leather upholstery, heated seats, and a premium audio system. Optional extras included a navigation system, a sunroof, and various towing packages. The interior design was functional and durable, prioritizing practicality over lavishness. The extended cab provided a usable rear seat area, suitable for occasional passengers or additional storage.
Chassis & Braking
The Sierra 3500HD’s chassis was designed to withstand the stresses of heavy-duty use. It featured a fully boxed frame for increased rigidity and durability. 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, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power even when heavily loaded. An Anti-lock Braking System (ABS) was standard, enhancing safety and control. The DRW configuration featured larger brakes and a wider track width, further improving stability and braking performance.
Market Reception & Comparison
The GMC Sierra 3500HD III with the 6.0L V8 engine was generally well-received by critics and consumers. It was praised for its robust construction, ample power, and comfortable ride. However, its fuel economy was a common criticism, particularly compared to the diesel engine option. The 6.0L V8 was often seen as a good choice for buyers who didn’t require the ultimate towing capacity of the Duramax diesel but still needed a capable heavy-duty truck. Compared to Ford’s Super Duty trucks and Dodge’s Ram HD models, the Sierra 3500HD offered a competitive combination of features, performance, and value.
Legacy
The GMT900 generation Sierra 3500HD, including the 6.0L V8 Automatic variant, has proven to be a durable and reliable truck. The Vortec LY6 engine is known for its longevity, and with proper maintenance, can provide many years of service. Today, these trucks are readily available on the used car market at relatively affordable prices. They remain popular among those needing a capable and dependable work truck. While fuel economy isn’t its strong suit, the 6.0L V8’s simplicity and relatively low maintenance costs make it an attractive option for budget-conscious buyers. The DRW configuration continues to be highly sought after by those requiring maximum towing and hauling capacity.
