The GMC Sierra 3500HD III, specifically the Crew Cab Long Box configuration with the 6.0-liter V8 engine and automatic transmission, represents a significant iteration in GMC’s heavy-duty truck lineage. Produced from 2007 through 2010 (GMT900 platform), this variant was aimed at buyers needing substantial towing and hauling capacity combined with the comfort of a crew cab. It occupied a sweet spot in the 3500HD lineup, offering a balance between capability and everyday usability, positioned above the standard cab and extended cab models, but below the more specialized work truck trims.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD III (GMT900) Crew 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 | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 8.1 kg/Hp, 123.9 Hp/tonne |
| Weight-to-torque ratio | 5.6 kg/Nm, 177.3 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 | 2905 kg, 6404.43 lbs |
| Max. weight | 5171 kg, 11400.1 lbs |
| Max load | 2266 kg, 4995.67 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%) | 5352 kg, 11799.14 lbs |
| Length | 6572 mm, 258.74 in |
| Width including mirrors | 2436 mm, 95.91 in |
| Height | 1931 mm, 76.02 in |
| Wheelbase | 4242 mm, 167.01 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 Crew Cab Long Box, powered by the 6.0-liter Vortec LY6 V8 and paired with a Hydra-Matic automatic transmission, debuted as part of GMC’s redesigned heavy-duty truck lineup in 2007. This generation (GMT900) represented a significant step forward in terms of interior refinement, ride quality, and overall capability compared to its predecessors. The Crew Cab configuration, with its four full-size doors and spacious rear seating, broadened the Sierra’s appeal beyond traditional work applications, attracting buyers who desired a heavy-duty truck for both professional and personal use. The “DRW” designation indicates a Dual Rear Wheel configuration, further enhancing towing and payload capacity.
Powertrain & Engine Architecture
At the heart of this Sierra 3500HD lies the Vortec LY6 6.0-liter V8 engine. This engine is a member of GM’s Vortec family, known for its robust construction and reliable performance. The LY6 features a cast iron block and aluminum cylinder heads, contributing to its durability. It utilizes a multi-port fuel injection system for precise fuel delivery and is equipped with an overhead valve (OHV) valvetrain. The engine produces 360 horsepower at 5400 rpm and 515 lb-ft of torque at 4200 rpm. The Hydra-Matic 6L80E six-speed automatic transmission was the standard pairing for this engine. This transmission offered smoother shifts and improved fuel economy compared to older four-speed automatics. The 6L80E features electronically controlled shifting and overdrive capabilities, optimizing performance for both highway cruising and heavy towing.
Driving Characteristics
The 6.0-liter V8 and 6L80E automatic combination provided a capable, though not overtly sporty, driving experience. The truck’s substantial weight (approximately 6,400 lbs) meant acceleration was brisk rather than quick. The automatic transmission was tuned for smooth operation and prioritized towing performance, meaning it wouldn’t downshift aggressively unless needed. The gear ratios were optimized for pulling heavy loads, providing ample torque in the lower gears. Compared to the available Duramax diesel engine, the 6.0L V8 offered less torque but a simpler, less expensive powertrain. Manual transmission versions of the Sierra 3500HD offered a more engaging driving experience, but the automatic was favored by many buyers for its convenience, especially when towing.
Equipment & Trim Levels
The Sierra 3500HD III Crew Cab Long Box 6.0L Automatic typically came standard with features like air conditioning, power windows and locks, a CD player, and cloth upholstery. Higher trim levels, such as the SLT and Denali, added features like leather upholstery, heated seats, a premium sound system, and chrome exterior trim. Optional extras included a navigation system, a sunroof, and various towing packages. The Crew Cab configuration provided ample space for five passengers, making it a comfortable option for families or crews. The Long Box bed offered a generous 76.63 cubic feet of cargo space.
Chassis & Braking
The Sierra 3500HD III utilized a fully boxed frame for enhanced rigidity and durability. The front suspension consisted of an independent torsion bar setup with double wishbone components, providing a relatively comfortable ride for a heavy-duty truck. The rear suspension employed a traditional leaf spring design, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes at all four corners, with ABS (Anti-lock Braking System) as standard equipment. The DRW configuration provided increased braking power and stability when towing heavy loads. Steering was accomplished via a cone worm and recirculation ball system.
Market Reception & Comparison
The 2007-2010 GMC Sierra 3500HD III was generally well-received by critics and consumers. The 6.0-liter V8 engine was praised for its reliability and adequate power for most tasks. However, it was often overshadowed by the more powerful and fuel-efficient Duramax diesel engine. Fuel economy with the 6.0L V8 was typical for a heavy-duty truck of its size, averaging around 14-16 mpg in mixed driving. Compared to the diesel, the gasoline engine offered a lower initial cost and simpler maintenance requirements. The Crew Cab configuration was a major selling point, providing a comfortable and spacious interior for passengers.
Legacy
The GMC Sierra 3500HD III 6.0L V8 Automatic has proven to be a relatively reliable powertrain in the used car market. The Vortec LY6 engine is known for its durability, and the 6L80E transmission is generally considered a robust unit. However, like all vehicles, these trucks are susceptible to age-related issues such as rust, worn suspension components, and potential oil leaks. Today, these trucks remain popular among buyers who need a capable and affordable heavy-duty truck for work or personal use. The combination of a spacious Crew Cab, a reliable V8 engine, and a capable automatic transmission makes it a compelling option in the used truck market.
