GMC Sierra 3500HD III (GMT900) Regular Cab Long Box 6.6 Duramax TD V8 (365 Hp) 4WD SRW Automatic
Overall Rating
GMC Sierra 3500HD:
The Chevrolet Silverado is a range of trucks manufactured by General Motors under the Chevrolet brand. Introduced for the 1999 model year, the Silverado is the successor to the long-running Chevrolet C/K model line. Taking its name from the top trim level from the Chevrolet C/K series, the Silverado is offered as a series of full-size pickup trucks, chassis cab trucks, and medium-duty trucks. The fourth generation of the model line was introduced for the 2019 model year.
The Chevrolet Silverado shares mechanical commonality with the identically related GMC Sierra; GMC ended the use of the C/K nomenclature a model generation prior to Chevrolet. In Mexico, high-trim level versions of the Silverado use the Chevrolet Cheyenne name. Competing against the Ford F-Series, Ram pickup, Toyota Tundra, and Nissan Titan, the Silverado is among the best-selling vehicles in the United States, having sold over 12 million trucks since its introduction in 1998 as a 1999 model year....(Read more on Wikipedia)
III (GMT900) Regular Cab Long Box Overview:
GMC Sierra 3500HD (III (GMT900) Regular Cab Long Box). With 895 Nm of torque, it offers ample pulling power. At around 2902 kg, it’s on the heavier side. All‑wheel drive provides excellent grip, ideal for off‑road use. A vehicle with an open cargo bed at the back, suitable for transporting goods. Seating for 2 makes it ideal for daily use.
6.6 Duramax TD V8 (365 Hp) 4WD SRW Automatic Verdict:
Performance Verdict
Excellent torque and power delivery from the Duramax diesel, making it highly capable for demanding towing and hauling with less effort.
Fuel Economy
Superior fuel economy compared to the gasoline V8, particularly when under load or on highway cruises, a key advantage for heavy-duty use.
Community Verdict
This rating is based on comments found on Reddit, scanned using artificial intelligence, and may not accurately reflect reality.

3.6 / 5
Based on AI analysis of 26 discussions
Read What Owners Say
Pros and Cons:
Pros:
- • Exceptional towing and hauling capabilities, especially with the Duramax diesel.
- • Robust and durable construction, built for demanding work.
- • Available 4WD and DRW options provide versatility and maximum stability.
- • Powerful engine options (Vortec LY6 and Duramax LMM) for various needs.
Cons:
- • Poor fuel economy, particularly with the gasoline V8.
- • Large size and weight can make maneuverability challenging in urban environments.
- • Ride quality can be stiff when unladen, typical for heavy-duty trucks.
- • Interior comfort and features are utilitarian, not luxury-focused.
Specifications:
| General: | |
|---|---|
| Brand: | GMC |
| Model: | Sierra 3500HD |
| Generation: | III (GMT900) Regular Cab Long Box |
| Modification (Engine): | 6.6 Duramax TD V8 (365 Hp) 4WD SRW Automatic |
| Start of production: | 2007 |
| End of production: | 2010 |
| Powertrain Architecture: | Internal Combustion engine |
| Body type: | Pick-up |
| Seats: | 2 |
| Doors: | 2 |
| Engine: | |
|---|---|
| Engine systems: | Particulate filter |
| Power: | 365 Hp @ 3200 rpm. |
| Power per litre: | 55.3 Hp/l |
| Torque: | 895 Nm @ 1600 rpm. |
| Engine Model/Code: | Duramax LMM |
| Engine displacement: | 6599 |
| Number of cylinders: | 8 |
| Engine configuration: | V-engine |
| Number of valves per cylinder: | 4 |
| Fuel injection system: | Diesel Commonrail |
| Engine aspiration: | Turbocharger, Intercooler |
| Valvetrain: | OHV |
| Engine oil capacity: | 9.5 l |
| Coolant: | 24 l |
| Engine layout: | Front, Longitudinal |
| Cylinder Bore: | 103 mm mm |
| Piston Stroke: | 99 mm mm |
| Compression ratio: | 16.8:1 |
| Maximum engine speed: | 3450 rpm. |
| Performance: | |
|---|---|
| Fuel Type: | Diesel |
| Weight-to-power ratio: | 8 kg/Hp, 125.8 Hp/tonne |
| Weight-to-torque ratio: | 3.2 kg/Nm, 308.4 Nm/tonne |
| Space: | |
|---|---|
| Kerb Weight: | 2902 |
| Max. weight: | 4490 |
| Max load: | 1588 |
| Trunk (boot) space - maximum: | 2170 l |
| Permitted trailer load with brakes (12%): | 5897 kg |
| Fuel tank capacity: | 129 l |
| Size: | |
|---|---|
| Length: | 5714 mm mm |
| Width: | 2436 mm mm |
| Height: | 1944 mm mm |
| Wheelbase: | 3378 mm mm |
| Width including mirrors: | 2436 mm |
| Front track: | 1742 mm |
| Rear (Back) track: | 1676 mm |
| Ride height (ground clearance): | 233 mm |
| Minimum turning circle (turning diameter): | 13.8 m |
| Powertrain: | |
|---|---|
| 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 (4x4) |
| Number of gears | 6 |
| Transmission type | Automatic |
| Gearbox type | Allison |
| Front brakes | Ventilated discs, 325x38 mm |
| Rear brakes | Ventilated discs, 325x30 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 265/75 R16; 265/70 R17; 225/75 R17 |
| Wheel rims size | 6.5J x 17; 7J x 16; 7.5J x 17 |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |










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