The GMC Sierra 1500 III, specifically the Extended Cab Long Box configuration with the 4.8-liter Vortec V8 engine and four-speed automatic transmission, was a mainstay of GMC’s full-size pickup truck lineup from 2010 to 2013. Representing the GMT900 generation, this variant occupied a middle ground within the Sierra 1500 range, offering a balance between capability, fuel efficiency, and affordability. It catered to buyers needing a versatile truck for both work and personal use, without the higher price tag of the more powerful engine options.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 III (GMT900) Extended Cab Long Box |
| Type (Engine) | 4.8 Vortec V8 (302 Hp) Automatic FlexFuel |
| Start of production | 2010 |
| End of production | 2013 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 6 |
| Doors | 2 |
| Fuel consumption (urban) | 16.8 l/100 km (14 US mpg) |
| Fuel consumption (extra urban) | 12.4 l/100 km (19 US mpg) |
| Fuel Type | Petrol / Ethanol – E85 |
| Power | 302 Hp @ 5600 rpm |
| Torque | 414 Nm @ 4600 rpm (305.35 lb.-ft. @ 4600 rpm) |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | L20 |
| Engine displacement | 4807 cm3 (293.34 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 96.01 mm (3.78 in.) |
| Piston Stroke | 83.06 mm (3.27 in.) |
| Compression ratio | 8.8:1 |
| 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 | 12.7 l (13.42 US qt | 11.17 UK qt) |
| Max. weight | 3130 kg (6900.47 lbs.) |
| Trunk (boot) space – maximum | 2138 l (75.5 cu. ft.) |
| Fuel tank capacity | 128 l (33.81 US gal | 28.16 UK gal) |
| Length | 6325 mm (249.02 in.) |
| Width including mirrors | 2031 mm (79.96 in.) |
| Height | 1870 mm (73.62 in.) |
| Wheelbase | 4001 mm (157.52 in.) |
| Front track | 1732 mm (68.19 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 | 15.3° |
| Departure angle | 24° |
| Ramp-over (brakeover) angle | 19.6° |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 4 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 |
INTRODUCTION
The GMC Sierra 1500 III, produced from 2007 to 2013, represented a significant update to GMC’s full-size pickup truck line. The Extended Cab Long Box configuration, paired with the 4.8L Vortec V8, offered a practical solution for buyers needing more passenger space than a regular cab, and a longer bed for hauling. This combination was particularly popular in the United States, where full-size pickups are a dominant force in the automotive market. The 4.8L engine, while not the most powerful option available, provided a good balance of performance and fuel economy, making it a sensible choice for everyday use.
Powertrain & Engine Architecture
The heart of this Sierra 1500 variant is the 4.8-liter (293 cubic inch) Vortec V8 engine, designated as the L20. This engine is a member of GM’s Vortec family, known for its robust construction and relatively simple design. It features a cast iron block and aluminum cylinder heads, with a two-valve-per-cylinder overhead valve (OHV) valvetrain. Fuel delivery is handled by a multi-port fuel injection system, providing precise fuel metering for optimal combustion. The engine produces 302 horsepower at 5600 rpm and 305 lb-ft of torque at 4600 rpm. The engine is FlexFuel capable, meaning it can run on gasoline or a blend of up to 85% ethanol (E85).
The engine is mated to a four-speed Hydra-Matic automatic transmission. This transmission, while not as sophisticated as newer transmissions with more gears, is known for its durability and reliability. The gear ratios are tuned for a balance of acceleration and fuel efficiency, prioritizing usability over outright performance. The transmission is electronically controlled, adapting to driving conditions and driver input.
Driving Characteristics
The 4.8L V8 and four-speed automatic combination delivers adequate, but not exhilarating, performance. Acceleration is sufficient for everyday driving and moderate towing, but it won’t win any drag races. The transmission shifts smoothly, but can feel somewhat dated compared to more modern automatics. The lower horsepower and torque figures compared to the 5.3L or 6.2L V8 options mean that this variant is less capable when hauling heavy loads or tackling steep inclines. However, the 4.8L’s lighter weight contributes to slightly better fuel economy. In real-world conditions, drivers could expect around 14-16 mpg in city driving and 18-20 mpg on the highway.
Equipment & Trim Levels
The 4.8L Sierra 1500 typically came standard with features like air conditioning, power windows and locks, and a basic audio system. The Extended Cab configuration added a second row of seating, although legroom in the rear was somewhat limited. Trim levels varied, but common options included upgraded cloth or leather upholstery, a premium audio system, power-adjustable seats, and a navigation system. The SLE and SLT trims were the most common upgrades, offering a more luxurious interior and additional features.
Chassis & Braking
The GMT900 Sierra 1500 utilizes a body-on-frame construction, providing a robust and durable platform. The front suspension consists of independent coil springs, while the rear suspension employs a traditional leaf spring setup. This configuration is designed to handle heavy loads and provide a comfortable ride. Braking duties are handled by disc brakes in the front and drum brakes in the rear. Anti-lock brakes (ABS) were standard equipment. The truck’s relatively high ground clearance (9.06 inches) allows for moderate off-road capability.
Market Reception & Comparison
Critics generally viewed the 4.8L Sierra 1500 as a sensible and practical choice for buyers who didn’t need the extra power of the larger engines. It offered a good value proposition, with a lower price tag and slightly better fuel economy than its more powerful siblings. Compared to the 5.3L V8, the 4.8L offered less towing capacity and acceleration, but it was also more affordable to purchase and operate. The 1.9L TDI versions of comparable European pickups offered significantly better fuel economy, but lacked the towing capacity and overall versatility of the Sierra 1500.
Legacy
The 4.8L Vortec V8, while no longer in production, remains a relatively reliable and durable engine. Properly maintained examples can still provide years of service. In the used car market, the 4.8L Sierra 1500 is often seen as a good value, offering a capable and affordable pickup truck. However, potential buyers should be aware of the age of the vehicle and the potential for maintenance issues associated with older trucks. The Hydra-Matic transmission, while generally reliable, may require attention as it ages. Overall, the 4.8L Sierra 1500 remains a popular choice for those seeking a dependable and versatile full-size pickup truck.
