The GMC Sierra 1500 III, specifically the Extended Cab Long Box configuration with the 5.3-liter Vortec V8 engine and four-wheel drive, was a prominent full-size pickup truck produced from 2007 to 2010. Representing the third generation of the Sierra 1500 (GMT900 platform), this variant occupied a sweet spot in the lineup, offering a balance of capability, space, and affordability for buyers needing a versatile work and family vehicle. It was positioned as a step up from the base models, providing more power and features than the smaller engine options, while remaining more accessible than the top-tier trims.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 III (GMT900) Extended Cab Long Box |
| Type (Engine) | 5.3 Vortec V8 (315 Hp) 4WD Automatic |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 6 |
| Doors | 2 |
| Fuel consumption (urban) | 16.8 l/100 km (14 US mpg, 16.8 UK mpg) |
| Fuel consumption (extra urban) | 12.4 l/100 km (19 US mpg, 22.8 UK mpg) |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.9 kg/Hp, 126.2 Hp/tonne |
| Weight-to-torque ratio | 5.4 kg/Nm, 183.5 Nm/tonne |
| Power | 315 Hp @ 5200 rpm |
| Power per litre | 59.1 Hp/l |
| Torque | 458 Nm @ 4400 rpm (337.8 lb.-ft. @ 4400 rpm) |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | LY5 |
| Engine displacement | 5328 cm3 (325.13 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 96.01 mm (3.78 in.) |
| Piston Stroke | 91.95 mm (3.62 in.) |
| Compression ratio | 9.9:1 |
| 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 capacity | 14.1 l (14.9 US qt | 12.41 UK qt) |
| Kerb Weight | 2496 kg (5502.74 lbs.) |
| Max. weight | 3175 kg (6999.68 lbs.) |
| Max load | 679 kg (1496.94 lbs.) |
| Trunk (boot) space – maximum | 2138 l (75.5 cu. ft.) |
| Fuel tank capacity | 128 l (33.81 US gal | 28.16 UK gal) |
| Permitted trailer load with brakes (12%) | 4173 kg (9199.89 lbs.) |
| Length | 6325 mm (249.02 in.) |
| Width including mirrors | 2029 mm (79.88 in.) |
| Height | 1868 mm (73.54 in.) |
| Wheelbase | 4001 mm (157.52 in.) |
| Front track | 1730 mm (68.11 in.) |
| Rear (Back) track | 1702 mm (67.01 in.) |
| Ride height (ground clearance) | 240 mm (9.45 in.) |
| Minimum turning circle (turning diameter) | 15.6 m (51.18 ft.) |
| Approach angle | 16.4° |
| Departure angle | 22° |
| Ramp-over (brakeover) angle | 17.8° |
| 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 coil spring |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Disc, 330×30 mm |
| Rear brakes | Drum, 295×60 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 245/70 R17 |
| Wheel rims size | 7.5J x 17 |
Powertrain & Engine Architecture
At the heart of this Sierra 1500 variant lies the 5.3-liter LY5 Vortec V8 engine. This engine is a member of the Vortec family, known for its robust construction and relatively simple design. The LY5 features a cast iron block and aluminum cylinder heads, contributing to its durability. It utilizes a 9.9:1 compression ratio and a multi-port fuel injection system for efficient combustion. The overhead valve (OHV) valvetrain, while not as technologically advanced as overhead cam designs, proved reliable and cost-effective. The engine produces 315 horsepower at 5200 rpm and 458 Nm (337.8 lb-ft) of torque at 4400 rpm. The Hydra-Matic 6-speed automatic transmission was the standard pairing for this engine. This transmission offered smooth shifting and helped optimize fuel economy compared to older 4-speed automatics. The transmission was electronically controlled, adapting to driving conditions for improved performance.
Driving Characteristics
The 5.3L V8 and 6-speed automatic combination provided a comfortable and capable driving experience. While not a performance-oriented setup, the engine delivered ample torque for towing and hauling. Acceleration was adequate for everyday driving, but noticeably slower than the available 6.0L V8. The automatic transmission’s gear ratios were tuned for a balance of fuel efficiency and usability. The 4WD system provided enhanced traction in inclement weather and off-road conditions. The ride quality, typical of full-size trucks, was generally comfortable, though the leaf spring rear suspension could feel somewhat stiff when unloaded.
Equipment & Trim Levels
The Extended Cab Long Box 5.3L 4WD Sierra 1500 typically came standard with features like air conditioning, power windows and locks, a CD player, and basic cloth upholstery. The Extended Cab configuration offered a second row of seating, albeit somewhat cramped, increasing passenger capacity. Optional extras included leather upholstery, a premium sound system, a navigation system, and a power sunroof. Trim levels varied, with SLE and SLT being common designations, offering progressively more features and refinements.
Chassis & Braking
The GMT900 platform featured a fully boxed frame for enhanced rigidity and durability. The front suspension utilized independent coil springs, providing a relatively comfortable ride. The rear suspension employed a traditional leaf spring setup, designed for load-carrying capacity. Braking duties were handled by disc brakes up front and drum brakes in the rear. An Anti-lock Braking System (ABS) was standard, enhancing safety during emergency stops. The truck’s relatively high ground clearance (240mm / 9.45 inches) allowed for moderate off-road capability.
Market Reception & Comparison
The Sierra 1500 with the 5.3L V8 and automatic transmission was well-received by consumers and critics alike. It was praised for its blend of capability, comfort, and value. Compared to the smaller 4.8L V8, the 5.3L offered a significant power boost, making it a more suitable choice for those who frequently towed or hauled heavy loads. Compared to the larger 6.0L V8, it offered better fuel economy, albeit at the expense of some performance. Fuel economy figures were around 16.8 l/100 km (14 US mpg) in the city and 12.4 l/100 km (19 US mpg) on the highway.
Legacy
The LY5 5.3L Vortec V8 proved to be a remarkably durable and reliable engine. Many examples are still on the road today, often with high mileage. The Hydra-Matic 6-speed automatic transmission also demonstrated good longevity. However, like many older vehicles, these trucks can be prone to rust, particularly in areas with harsh winters. In the used car market, these Sierra 1500s remain popular choices for those seeking a capable and affordable full-size pickup truck. Their relatively simple mechanical design makes them easier and less expensive to maintain compared to more modern, technologically advanced trucks.
