The GMC Sierra 1500 III, specifically the Regular 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 as part of the GMT900 platform generation, this variant aimed to balance capability with affordability within the Sierra 1500 range. It served as a work-focused option, appealing to buyers prioritizing hauling and towing capacity over luxury features. This model year marked a substantial redesign for the Sierra, incorporating improved styling, enhanced interior materials, and a more refined driving experience compared to its predecessor.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 III (GMT900) Regular 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 | 3 |
| 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 | 6.8 kg/Hp, 146.2 Hp/tonne |
| Weight-to-torque ratio | 4.7 kg/Nm, 212.5 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 | 2155 kg (4750.96 lbs.) |
| Max. weight | 2903 kg (6400.02 lbs.) |
| Max load | 748 kg (1649.06 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%) | 4536 kg (10000.17 lbs.) |
| Length | 5702 mm (224.49 in.) |
| Width including mirrors | 2031 mm (79.96 in.) |
| Height | 1867 mm (73.5 in.) |
| Wheelbase | 3378 mm (132.99 in.) |
| Front track | 1730 mm (68.11 in.) |
| Rear (Back) track | 1702 mm (67.01 in.) |
| Ride height (ground clearance) | 208 mm (8.19 in.) |
| Minimum turning circle (turning diameter) | 15.4 m (50.52 ft.) |
| Approach angle | 16° |
| Departure angle | 24.1° |
| Ramp-over (brakeover) angle | 21.5° |
| 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 engine is longitudinally mounted, driving the rear wheels. Paired with the LY5 is the 4L80-E four-speed automatic transmission, a Hydra-Matic unit known for its strength and ability to handle high torque loads. While not offering the fuel efficiency of more modern transmissions, the 4L80-E was a workhorse, well-suited to the demands of towing and hauling.
Driving Characteristics
The 5.3L V8 and 4L80-E automatic combination delivered adequate, though not exhilarating, performance. Acceleration was sufficient for everyday driving and moderate towing, but it lacked the responsiveness of the higher-output 6.0L V8 or the agility of models equipped with manual transmissions. The four-speed automatic, while durable, had relatively wide gear ratios, which could result in the engine feeling strained during highway passing maneuvers. The truck’s weight and the automatic transmission’s programming prioritized smooth operation and durability over outright speed. The long bed configuration further impacted handling, making the truck feel less nimble than shorter wheelbase models. However, the suspension provided a comfortable ride, even when carrying a load.
Equipment & Trim Levels
The Regular Cab Long Box 5.3L Automatic Sierra 1500 typically occupied a mid-range position in the lineup. Standard features generally included air conditioning, a basic audio system, vinyl upholstery, and manual windows and locks. Work Truck (WT) trims were particularly spartan, focusing on functionality. Higher trims, such as SLE, added features like cloth upholstery, power windows and locks, and upgraded audio systems. Optional extras included a towing package, upgraded wheels, and a premium audio system. The interior design was functional and durable, prioritizing practicality over luxury.
Chassis & Braking
The GMT900 platform utilized a body-on-frame construction, providing a robust foundation for heavy-duty use. The front suspension consisted of independent coil springs, while the rear suspension employed a traditional leaf spring setup. This configuration prioritized load-carrying capacity and durability. Braking duties were handled by disc brakes at the front and drum brakes at the rear. Anti-lock braking system (ABS) was standard. The truck’s steering utilized a rack-and-pinion system with power assist, providing reasonable steering feel and maneuverability.
Market Reception & Comparison
The 2007-2010 GMC Sierra 1500 with the 5.3L V8 and automatic transmission was generally well-received by critics and consumers. It offered a good balance of capability, comfort, and value. Fuel economy, however, was a common criticism, averaging around 14-20 mpg in real-world driving. Compared to the 4.8L V8 models, the 5.3L offered significantly more power and torque, making it a better choice for towing and hauling. Compared to the 6.0L V8, it offered a slight fuel economy advantage but lacked the ultimate power output. The 5.3L automatic was often seen as a sweet spot in the lineup, providing sufficient performance for most users without the higher price tag of the 6.0L.
Legacy
The LY5 5.3L Vortec V8, when paired with the 4L80-E transmission, has proven to be a remarkably durable powertrain. These trucks are still commonly found on the road today, often with high mileage. While maintenance is relatively straightforward, common issues include oil leaks, sensor failures, and wear and tear on the transmission. The engine’s robust design and readily available parts contribute to its longevity. In the used car market, these Sierras represent a relatively affordable option for those seeking a capable and reliable full-size pickup truck. Their work-oriented nature and proven powertrain make them a popular choice for tradesmen, farmers, and anyone needing a dependable vehicle for hauling and towing.
