The GMC Sierra 1500 V (GMTT1XX) Double Cab, equipped with the 5.3-liter V8 engine producing 355 horsepower and paired with a 10-speed automatic transmission and four-wheel drive, was a key offering in GMC’s full-size pickup truck lineup from the 2018 to 2021 model years. This configuration represented a balance between capability, comfort, and price within the broader Sierra 1500 range, targeting buyers who needed substantial towing and hauling capacity but didn’t necessarily require the higher performance or luxury features of the Denali trim. The GMTT1XX designation refers to the truck’s platform, a significant update to the previous GMT900 series, bringing improvements in ride quality, technology, and safety.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 V (GMTT1XX) Double Cab |
| Type (Engine) | 5.3 V8 (355 Hp) 4WD 10 Automatic |
| Start of production | 2018 |
| End of production | 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 14.7 l/100 km (16 US mpg, 19.2 UK mpg, 6.8 km/l) |
| Fuel consumption (extra urban) | 11.2 l/100 km (21 US mpg, 25.2 UK mpg, 8.9 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 6.3 kg/Hp, 159.1 Hp/tonne |
| Weight-to-torque ratio | 4.3 kg/Nm, 232.6 Nm/tonne |
| Power | 355 Hp @ 5600 rpm |
| Power per litre | 66.6 Hp/l |
| Torque | 519 Nm @ 4100 rpm (382.79 lb.-ft. @ 4100 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | L84 |
| Engine displacement | 5328 cm3 (325.13 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 96 mm (3.78 in.) |
| Piston Stroke | 92 mm (3.62 in.) |
| Compression ratio | 11:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Direct injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV, VVT DI |
| Engine oil capacity | 7.6 l (8.03 US qt | 6.69 UK qt) |
| Coolant capacity | 13.1 l (13.84 US qt | 11.53 UK qt) |
| Kerb Weight | 2231 kg (4918.51 lbs.) |
| Max. weight | 3175 kg (6999.68 lbs.) |
| Max load | 944 kg (2081.16 lbs.) |
| Fuel tank capacity | 91 l (24.04 US gal | 20.02 UK gal) |
| Permitted trailer load with brakes (12%) | 4173 kg (9199.89 lbs.) |
| Length | 5886 mm (231.73 in.) |
| Width including mirrors | 2063 mm (81.22 in.) |
| Height | 1921 mm (75.63 in.) |
| Wheelbase | 3745 mm (147.44 in.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| Number of gears and type of gearbox | 10 gears, automatic transmission |
| Front suspension | Independent coil spring |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 330×30 mm |
| Rear brakes | Ventilated discs, 345×20 mm |
| Tires size | 255/70 R17; 265/70 R17; 265/65 R18 |
| Wheel rims size | 8.0J x 17; 8.5J x 18 |
Powertrain & Engine Architecture
The heart of this Sierra 1500 variant is the 5.3-liter L84 V8 engine. This engine is a member of GM’s Small Block family, known for its durability and relatively simple design. The L84 features direct injection, a significant upgrade over earlier iterations, improving fuel efficiency and power output. The direct injection system precisely meters fuel directly into the combustion chamber, allowing for more complete combustion. It also incorporates Active Fuel Management (AFM), or cylinder deactivation, which shuts down four cylinders during light-load cruising to further enhance fuel economy. The engine utilizes an overhead valve (OHV) valvetrain with variable valve timing (VVT) to optimize performance across the engine’s operating range. The 10-speed automatic transmission (10L80) is a crucial component, offering a wide gear ratio spread for improved acceleration, towing capability, and fuel efficiency. This transmission replaced the older 8-speed automatic, providing smoother shifts and more precise control.
Driving Characteristics
The 5.3L V8 with the 10-speed automatic delivers a comfortable and capable driving experience. While not as quick as the available 6.2-liter V8, the 5.3L provides ample power for everyday driving and towing. The 10-speed transmission keeps the engine in its optimal power band, resulting in responsive acceleration. The wide gear ratios also contribute to a lower engine speed at highway speeds, reducing noise and improving fuel economy. Compared to the 2.7-liter turbocharged four-cylinder or the 5.3L with a manual transmission, this configuration prioritizes ease of use and smooth power delivery. The automatic transmission eliminates the need for frequent shifting, making it ideal for drivers who prefer a relaxed driving experience. However, the automatic does slightly diminish the feeling of direct control compared to a manual transmission.
Equipment & Trim Levels
The Double Cab configuration offered a spacious interior with seating for five passengers. Standard features on the Sierra 1500 V typically included air conditioning, power windows and locks, a basic infotainment system with a touchscreen display, and a rearview camera. Higher trim levels, such as the SLE and Elevation, added features like leather upholstery, heated seats, a premium sound system, and advanced safety technologies. Optional extras included a navigation system, a sunroof, and various driver-assistance features like lane departure warning and blind-spot monitoring. The Double Cab body style provided a good balance between passenger space and bed length, making it a versatile option for both work and family use.
Chassis & Braking
The Sierra 1500 V (GMTT1XX) utilizes a fully boxed frame for enhanced strength and rigidity. The front suspension features independent coil springs, providing a comfortable ride and good handling. The rear suspension employs a traditional leaf spring setup, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) is standard. The four-wheel-drive system offers various modes, including 2WD, 4HI, and 4LO, allowing drivers to adapt to different road conditions. The steering system is an electric power-assisted rack-and-pinion setup, providing precise steering feel and reduced driver effort.
Market Reception & Comparison
The GMC Sierra 1500 V with the 5.3L V8 and 10-speed automatic was generally well-received by automotive critics. It was praised for its comfortable ride, spacious interior, and capable towing capacity. Fuel economy was considered adequate for a full-size pickup truck, although not class-leading. Compared to the Ford F-150 and Ram 1500, the Sierra 1500 offered a slightly more refined interior and a more robust feel. The 5.3L V8 offered a good balance between power and fuel efficiency, making it a popular choice for buyers who didn’t need the extra performance of the 6.2L V8. However, some critics noted that the interior design was starting to feel dated compared to its competitors.
Legacy
The L84 5.3L V8 engine has proven to be a reliable and durable powertrain. With proper maintenance, these engines can easily exceed 200,000 miles. The 10L80 transmission has also demonstrated good reliability, although some owners have reported minor issues with shift quality. On the used car market, the 2018-2021 GMC Sierra 1500 V with this configuration represents a good value, offering a capable and comfortable pickup truck at a reasonable price. Its blend of power, efficiency, and features makes it a popular choice for buyers seeking a versatile and dependable full-size truck.
