The GMC Sierra 1500 III, specifically the Extended Cab Long Box configuration with the 4.8-liter Vortec V8 engine, 4WD, and automatic transmission, was a popular full-size pickup truck produced from 2010 to 2013. Representing the third generation of the Sierra 1500 (GMT900 platform), this variant occupied a middle ground in the lineup, 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) 4WD 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) | 18.1 l/100 km (13 US mpg, 15.6 UK mpg, 5.5 km/l) |
| Fuel consumption (extra urban) | 13.1 l/100 km (18 US mpg, 21.6 UK mpg, 7.6 km/l) |
| Fuel Type | Petrol / Ethanol – E85 |
| Power | 302 Hp @ 5600 rpm |
| Power per litre | 62.8 Hp/l |
| 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 | 3175 kg (6999.68 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 | 1868 mm (73.54 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) | 240 mm (9.45 in.) |
| Minimum turning circle (turning diameter) | 15.6 m (51.18 ft.) |
| Approach angle | 15.5° |
| Departure angle | 23.3° |
| Ramp-over (brakeover) angle | 19.3° |
| 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 | 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 |
Powertrain & Engine Architecture
The heart of this Sierra 1500 variant was the 4.8-liter (293 cubic inch) Vortec 4800 V8 engine, designated as the L20. This engine was a member of the Vortec family, known for its robust design and relatively simple architecture. It featured a cast iron block and aluminum cylinder heads, utilizing a 90-degree V-angle. The engine employed a traditional overhead valve (OHV) valvetrain with two valves per cylinder. Fuel delivery was handled by a multi-port fuel injection system, providing adequate fuel atomization for efficient combustion. The L20 was also FlexFuel capable, meaning it could run on gasoline or a blend of up to 85% ethanol (E85). The engine was mated to a four-speed Hydra-Matic automatic transmission, a common and reliable unit for GM trucks of this era. This transmission was electronically controlled, offering smooth shifts and adaptive shift patterns.
Driving Characteristics
The 4.8L V8 with the four-speed automatic provided adequate, though not exhilarating, performance. With 302 horsepower and 305 lb-ft of torque, acceleration was sufficient for everyday driving and towing moderate loads. The automatic transmission’s gear ratios were optimized for towing and hauling, prioritizing low-end torque over outright speed. Compared to the available 5.3L and 6.2L V8 options, the 4.8L felt less powerful, especially when fully loaded or climbing steep hills. However, it offered a noticeable improvement in fuel economy. The 4×4 system provided enhanced traction in inclement weather and off-road conditions, making it a capable all-weather vehicle. The ride quality, typical of a full-size truck, was firm but generally comfortable, especially with the long wheelbase of the Extended Cab configuration.
Equipment & Trim Levels
The Extended Cab Long Box 4.8L 4WD Sierra 1500 typically came standard with features like air conditioning, power windows and locks, a basic audio system, and a tilt steering wheel. The interior typically featured cloth upholstery and a relatively simple dashboard layout. Popular optional extras included upgraded audio systems, leather upholstery, power-adjustable seats, a navigation system, and a rear vision camera. Trim levels varied, but generally included base models and more upscale SLE and SLT trims. The SLE trim added features like chrome exterior accents, upgraded interior materials, and additional convenience features. The SLT trim offered the highest level of luxury, with leather upholstery, premium audio, and advanced features like heated seats.
Chassis & Braking
The Sierra 1500 III utilized a body-on-frame construction, providing a robust and durable platform. The front suspension consisted of independent coil springs, while the rear suspension employed a traditional leaf spring setup. This configuration was designed to handle heavy loads and provide a comfortable ride. Brakes were disc brakes in the front and drum brakes in the rear, equipped with an Anti-lock Braking System (ABS) for enhanced safety. The 4WD system was typically a part-time system, allowing the driver to switch between two-wheel drive and four-wheel drive as needed. The truck’s relatively high ground clearance (9.45 inches) provided good off-road capability.
Market Reception & Comparison
The 4.8L Sierra 1500 was generally well-received by critics and consumers as a practical and affordable full-size truck. It offered a good balance of capability and fuel economy, making it a popular choice for buyers who didn’t need the extra power of the larger V8 engines. Compared to the 5.3L V8, the 4.8L offered better fuel economy but less towing capacity and acceleration. The 4.8L also tended to be more reliable than the 5.3L, which was prone to oil consumption issues in some model years. Against competitors like the Ford F-150 and Ram 1500, the Sierra 1500 offered a competitive package with a strong reputation for durability.
Legacy
The 4.8L Vortec V8, while not the most powerful engine in the Sierra 1500 lineup, proved to be a reliable and durable powertrain. These trucks are still commonly found on the used car market today, often with high mileage but still in good working condition. The L20 engine is known for its relatively simple design, making it easier and less expensive to maintain than more complex engines. While fuel economy isn’t exceptional by modern standards, it remains adequate for many users. The GMT900 Sierra 1500, particularly the 4.8L variant, represents a solid and dependable full-size truck that continues to provide value to its owners.
