The GMC Sierra 1500 III, specifically the Extended Cab Long Box configuration with the 5.3-liter Vortec V8 engine and automatic transmission, represents a significant iteration in GMC’s full-size pickup truck lineage. Produced from 2007 through 2010, this variant occupied a sweet spot in the Sierra 1500 lineup, offering a balance of capability, space, and affordability. It was part of the GMT900 platform generation, a substantial redesign that aimed to improve interior space, ride quality, and overall refinement compared to its predecessor. This particular trim level catered to buyers needing a versatile truck for both work and family use, providing ample passenger room and a sizable cargo bed.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 III (GMT900) Extended Cab Long Box |
| Type (Engine) | 5.3 Vortec V8 (315 Hp) 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) | 11.8 l/100 km (19.9 US mpg, 23.9 UK mpg) |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.5 kg/Hp, 132.5 Hp/tonne |
| Weight-to-torque ratio | 5.2 kg/Nm, 192.6 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 | 2378 kg (5242.59 lbs.) |
| Max. weight | 3130 kg (6900.47 lbs.) |
| Max load | 752 kg (1657.88 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%) | 4309 kg (9499.72 lbs.) |
| Length | 6325 mm (249.02 in.) |
| Width including mirrors | 2029 mm (79.88 in.) |
| Height | 1870 mm (73.62 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) | 230 mm (9.06 in.) |
| Minimum turning circle (turning diameter) | 15.6 m (51.18 ft.) |
| Approach angle | 16.2° |
| Departure angle | 22.8° |
| Ramp-over (brakeover) angle | 18° |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| 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 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’s gear ratios were tuned for a balance of towing capability and everyday drivability.
Driving Characteristics
The 5.3L V8 and 6-speed automatic combination delivered a capable, if not exhilarating, driving experience. Acceleration was adequate for most situations, but the truck wasn’t designed for sporty performance. The automatic transmission generally shifted smoothly, although some drivers noted a slight hesitation during downshifts. The truck’s weight and rear-wheel-drive configuration meant it wasn’t particularly nimble, but it provided a stable and comfortable ride. The long bed configuration, while offering substantial cargo capacity, did impact handling slightly, making it feel longer and less responsive than shorter wheelbase models. Compared to the 4.8L V8 option, the 5.3L provided a noticeable increase in power, making it better suited for towing and hauling heavier loads. Compared to the more fuel-efficient but less powerful 4.3L V6, the 5.3L offered a significant performance upgrade.
Equipment & Trim Levels
The Extended Cab Long Box 5.3L Sierra 1500 typically came standard with features like air conditioning, power windows and locks, and a basic audio system. The extended cab provided additional seating for passengers, although the rear seats were best suited for occasional use. 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, sunroof, and upgraded towing packages. Interior materials were generally durable and functional, reflecting the truck’s work-oriented nature.
Chassis & Braking
The Sierra 1500 III utilized a body-on-frame construction, providing a robust and durable platform. The front suspension featured independent coil springs, while the rear suspension employed a traditional leaf spring setup. This configuration offered a good balance of ride comfort and 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 steering system utilized a rack-and-pinion setup with power assist, providing reasonably precise steering feel.
Market Reception & Comparison
The 2007-2010 GMC Sierra 1500 with the 5.3L V8 and automatic transmission was well-received by critics and consumers alike. It was praised for its spacious interior, comfortable ride, and strong towing capability. Fuel economy, however, was a common criticism, as the 5.3L V8 wasn’t particularly fuel-efficient. Compared to the Ford F-150 and Ram 1500, the Sierra 1500 offered a competitive package, with a reputation for reliability and durability. The 5.3L engine offered a good compromise between power and fuel economy, making it a popular choice for buyers who needed a capable truck for both work and personal use.
Legacy
The LY5 5.3L Vortec V8 engine, when paired with the 6-speed automatic, has proven to be a relatively reliable powertrain. While not immune to common GM truck issues like active fuel management (AFM) problems, these engines generally hold up well with proper maintenance. Today, these Sierra 1500s are readily available on the used car market at affordable prices. They remain a popular choice for buyers seeking a capable and dependable full-size pickup truck. Their relatively simple design and readily available parts make them relatively easy to maintain and repair, contributing to their continued popularity among truck enthusiasts and those needing a workhorse vehicle.
