The GMC Sierra 1500 V (GMTT1XX) Double Cab, equipped with the 3.0 Duramax Turbo-Diesel engine producing 277 horsepower, was a mid-cycle offering within the fourth generation of the Sierra 1500 pickup truck. Introduced for the 2019 model year and continuing through 2021, this variant aimed to provide a balance between capability, fuel efficiency, and refinement for truck buyers. It occupied a position between the base gasoline-powered engines and the more powerful 6.2-liter V8, targeting customers who prioritized towing capacity and long-distance comfort over outright acceleration. The GMTT1XX platform represented a significant update to the Sierra 1500, incorporating modern technologies and design elements.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 V (GMTT1XX) Double Cab |
| Type (Engine) | 3.0 Duramax TD (277 Hp) Automatic |
| Start of production | 2019 |
| End of production | 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 10.2 l/100 km (23.1 US mpg) |
| Fuel consumption (extra urban) | 7.8 l/100 km (30.2 US mpg) |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8 kg/Hp, 124.9 Hp/tonne |
| Weight-to-torque ratio | 3.6 kg/Nm, 280.9 Nm/tonne |
| Power | 277 Hp @ 3750 rpm |
| Power per litre | 92.3 Hp/l |
| Torque | 623 Nm @ 1500 rpm (459.5 lb.-ft. @ 1500 rpm) |
| Maximum engine speed | 5100 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | LM2 |
| Engine displacement | 3000 cm3 (183.07 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 15:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 6.6 l (6.97 US qt | 5.81 UK qt) |
| Coolant capacity | 19.1 l (20.18 US qt | 16.81 UK qt) |
| Kerb Weight | 2218 kg (4889.85 lbs.) |
| Max. weight | 3220 kg (7098.88 lbs.) |
| Max load | 1002 kg (2209.03 lbs.) |
| Fuel tank capacity | 83 l (21.93 US gal | 18.26 UK gal) |
| AdBlue tank capacity | 20.3 l (5.36 US gal | 4.47 UK gal) |
| Permitted trailer load with brakes (12%) | 4082 kg (8999.27 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 | Rear wheel drive |
| 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 |
| Wheel rims size | 8J x 17 |
Powertrain & Engine Architecture
The heart of this Sierra 1500 variant is the LM2 3.0-liter inline-six cylinder Duramax turbo-diesel engine. This engine represents a departure from traditional V-style diesel configurations, offering a more compact design. The LM2 utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) and intercooler work in tandem to enhance power and efficiency. The engine features a double overhead camshaft (DOHC) valvetrain with four valves per cylinder, contributing to its responsive nature. The 10-speed automatic transmission, a General Motors collaboration with Ford, was specifically tuned to complement the diesel engine’s torque curve. This transmission provides a wide range of gear ratios, optimizing both fuel economy and towing performance.
Driving Characteristics
The 3.0 Duramax-powered Sierra 1500 Double Cab delivers a markedly different driving experience compared to its gasoline counterparts. While not offering the immediate acceleration of the larger V8, the diesel engine provides a substantial amount of low-end torque – 459.5 lb.-ft. – making it exceptionally capable for towing and hauling. The 10-speed automatic transmission keeps the engine within its optimal power band, resulting in smooth and confident acceleration. The gear ratios are well-spaced, allowing for relaxed highway cruising and responsive downshifts when needed. Compared to the 5.3L V8, the diesel offers superior fuel economy, particularly during highway driving. However, the diesel engine is noticeably louder and exhibits more vibration than the gasoline engines.
Equipment & Trim Levels
The 3.0 Duramax engine was typically offered on SLE, Elevation, and AT4 trim levels of the Sierra 1500 Double Cab. Standard equipment generally included features like an 8-inch touchscreen infotainment system with Apple CarPlay and Android Auto compatibility, a rearview camera, and keyless entry. Higher trim levels, such as the AT4, added features like leather upholstery, heated and ventilated front seats, a premium audio system, and advanced safety technologies like adaptive cruise control and lane keeping assist. Optional extras included a power sunroof, a bed liner, and various towing packages.
Chassis & Braking
The Sierra 1500 Double Cab utilizes a fully boxed frame for enhanced rigidity and durability. The front suspension consists of independent coil springs, while the rear suspension employs a traditional leaf spring setup. This configuration provides a comfortable ride quality while maintaining a respectable payload capacity. The braking system features ventilated discs on all four wheels, providing ample stopping power. Anti-lock brakes (ABS) are standard, along with electronic stability control. The rear brakes on some configurations were smaller than the front, reflecting the weight distribution of the vehicle.
Market Reception & Comparison
The 3.0 Duramax Sierra 1500 received generally positive reviews from automotive critics. It was praised for its fuel efficiency, strong towing capacity, and refined interior. However, some reviewers noted the engine’s noise and vibration compared to gasoline alternatives. Compared to the 5.3L V8, the Duramax offered significantly better fuel economy, making it an attractive option for those who frequently tow or drive long distances. The Duramax also provided a more competitive alternative to diesel offerings from Ford and Ram. Reliability reports have been generally favorable, with the LM2 engine proving to be a durable and dependable powerplant.
Legacy
The LM2 3.0-liter Duramax engine has established itself as a reliable and efficient option in the half-ton pickup truck segment. While the Sierra 1500 with this engine was only produced for a few model years, it remains a popular choice on the used car market. Its combination of fuel economy, towing capability, and comfortable ride quality continues to appeal to a wide range of truck buyers. The engine’s robust design and relatively simple maintenance requirements contribute to its long-term dependability, making it a solid investment for those seeking a capable and efficient full-size pickup truck.
