Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 III (GMT900) Crew Cab Short Box |
| Type (Engine) | 5.3 Vortec V8 (320 Hp) 4WD Automatic FlexFuel |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 6 |
| Doors | 4 |
| 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 / Ethanol – E85 |
| Power | 320 Hp @ 5200 rpm |
| Power per litre | 60.1 Hp/l |
| Torque | 461 Nm @ 4200 rpm (340.02 lb.-ft. @ 4200 rpm) |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | LMG |
| 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) |
| Max. weight | 3175 kg (6999.68 lbs.) |
| Trunk (boot) space – maximum | 1506 l (53.18 cu. ft.) |
| Fuel tank capacity | 98 l (25.89 US gal | 21.56 UK gal) |
| Permitted trailer load with brakes (12%) | 4309 kg (9499.72 lbs.) |
| Length | 5844 mm (230.08 in.) |
| Width including mirrors | 2031 mm (79.96 in.) |
| Height | 1872 mm (73.7 in.) |
| Wheelbase | 3645 mm (143.5 in.) |
| Front track | 1730 mm (68.11 in.) |
| Rear (Back) track | 1702 mm (67.01 in.) |
| Ride height (ground clearance) | 229 mm (9.02 in.) |
| Minimum turning circle (turning diameter) | 14.4 m (47.24 ft.) |
| Approach angle | 15.3° |
| Departure angle | 22.4° |
| Ramp-over (brakeover) angle | 19.3° |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| 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 |
The GMC Sierra 1500 III, launched in 2006 as a 2007 model, represented a significant update to GMC’s full-size pickup truck line. Built on the GMT900 platform, shared with the Chevrolet Silverado, the Sierra aimed to provide a more refined and upscale experience compared to its Chevrolet counterpart. The Crew Cab configuration, offering four full-size doors and a spacious rear seat, became increasingly popular for families and those needing passenger capacity alongside truck functionality. The 5.3-liter Vortec V8 engine paired with a four-speed automatic transmission was a mainstay of the lineup, offering a compelling blend of power and efficiency for the majority of buyers.
Powertrain & Engine Architecture
The heart of this Sierra 1500 is the 5.3-liter (325 cubic inch) Vortec 5300 V8 engine, designated as the LMG engine code. This engine is a traditional overhead valve (OHV) design, known for its simplicity and durability. It features a cast iron block with aluminum cylinder heads. The LMG utilizes multi-port fuel injection, delivering fuel directly to each cylinder for optimized combustion. The engine produces 320 horsepower at 5200 rpm and 340 lb-ft of torque at 4200 rpm. The 5.3L engine was also FlexFuel capable, meaning it could run on gasoline or a blend of up to 85% ethanol (E85). The transmission is a four-speed automatic, the Hydra-Matic 4L80-E, a robust and reliable unit known for its durability. While not as technologically advanced as some newer transmissions, the 4L80-E provided smooth shifts and adequate performance for the intended application.
Driving Characteristics
The 5.3L V8 and 4-speed automatic combination in the Sierra 1500 offered a comfortable and capable driving experience. Acceleration was adequate for everyday driving and towing, though not particularly sporty. The automatic transmission’s gear ratios were optimized for towing and hauling, resulting in a slightly lower first gear for improved off-the-line performance when loaded. Compared to the available 6.0L V8, the 5.3L offered less raw power, but it also delivered better fuel economy. Compared to the diesel options, the 5.3L lacked the low-end torque of the Duramax diesel, making it less ideal for heavy-duty towing. The ride quality, typical of full-size trucks, was generally comfortable, though the leaf spring rear suspension could be somewhat firm when unloaded.
Equipment & Trim Levels
The Sierra 1500 Crew Cab with the 5.3L engine was typically offered in SLE, SLT, and Denali trim levels. The SLE trim served as the base model, including features like air conditioning, power windows and locks, and a basic audio system. The SLT trim added features such as leather upholstery, heated front seats, and upgraded audio. The Denali trim represented the pinnacle of luxury, offering premium leather, wood trim, and a host of convenience features. Standard features on most models included a tilt steering wheel, cruise control, and a CD player. Optional extras included a navigation system, sunroof, and upgraded sound systems.
Chassis & Braking
The GMT900 platform featured a fully boxed frame for increased rigidity and strength. The front suspension utilized an independent coil spring design, providing a comfortable ride. The rear suspension employed a traditional leaf spring setup, designed for load-carrying capability. Brakes were disc brakes in the front (330x30mm) and drum brakes in the rear (295x60mm). Anti-lock brakes (ABS) were standard. The steering system was a rack-and-pinion setup with power assist. The standard tire size was 245/70R17, mounted on 7.5J x 17 inch wheels.
Market Reception & Comparison
The GMC Sierra 1500 with the 5.3L V8 and automatic transmission was well-received by critics and consumers alike. It was praised for its comfortable ride, spacious interior, and capable powertrain. Fuel economy was considered average for a full-size truck, but the FlexFuel capability offered an alternative fuel option. Compared to the Chevrolet Silverado, the Sierra was often seen as a more refined and upscale option. The 5.3L engine offered a good balance between power and efficiency, making it a popular choice for buyers who didn’t need the extra power of the 6.0L V8 or the towing capacity of the Duramax diesel. Reliability was generally good, though some owners reported issues with the active fuel management system (AFM), which deactivated cylinders to improve fuel economy.
Legacy
The GMT900 Sierra 1500, particularly the 5.3L V8/Automatic combination, remains a popular choice in the used truck market. The LMG engine is known for its durability and relatively low maintenance costs. While the four-speed automatic transmission is not as efficient as newer transmissions, it has proven to be reliable. Common issues include oil leaks and occasional AFM problems. These trucks offer a good value for buyers seeking a capable and comfortable full-size pickup at an affordable price. The Sierra 1500 III established GMC as a premium truck brand, setting the stage for future generations of Sierra pickups.
