The GMC Sierra 3500HD III, specifically the Crew Cab Standard Box configuration with the 6.6-liter Duramax Turbo Diesel V8 engine and four-wheel drive, represents a significant iteration in GMC’s heavy-duty truck lineage. Produced from 2011 to 2013 as part of the GMT900 platform’s facelift, this variant was aimed at buyers needing substantial towing and hauling capacity combined with a degree of interior comfort. It occupied a premium position within the Sierra 3500HD lineup, offering a powerful diesel engine paired with an automatic transmission, making it a popular choice for both commercial and personal use. This model year saw refinements to the GMT900 platform, enhancing both its capabilities and its appeal in a competitive segment.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD III (GMT900, facelift 2011) Crew Cab Standard Box |
| Type (Engine) | 6.6 Duramax TD V8 (397 Hp) 4WD SRW Automatic |
| Start of production | 2011 |
| End of production | 2013 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 8.4 kg/Hp, 118.7 Hp/tonne |
| Weight-to-torque ratio | 3.2 kg/Nm, 310 Nm/tonne |
| Power | 397 Hp @ 3000 rpm |
| Power per litre | 60.2 Hp/l |
| Torque | 1037 Nm @ 1600 rpm (764.85 lb.-ft. @ 1600 rpm) |
| Maximum engine speed | 3000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax LML |
| Engine displacement | 6599 cm3 (402.7 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103 mm (4.06 in.) |
| Piston Stroke | 99 mm (3.9 in.) |
| Compression ratio | 16:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | OHV |
| Engine oil capacity | 9.5 l (10.04 US qt | 8.36 UK qt) |
| Coolant | 24 l (25.36 US qt | 21.12 UK qt) |
| Kerb Weight | 3345 kg (7374.46 lbs.) |
| Max. weight | 5216 kg (11499.31 lbs.) |
| Max load | 1871 kg (4124.85 lbs.) |
| Trunk (boot) space – maximum | 1718 l (60.67 cu. ft.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 5897 kg (13000.66 lbs.) |
| Length | 6101 mm (240.2 in.) |
| Width including mirrors | 2032 mm (80 in.) |
| Height | 1966 mm (77.4 in.) |
| Wheelbase | 3904 mm (153.7 in.) |
| Front track | 1748 mm (68.82 in.) |
| Rear (Back) track | 1709 mm (67.28 in.) |
| Ride height (ground clearance) | 213 mm (8.39 in.) |
| Minimum turning circle (turning diameter) | 15.4 m (50.52 ft.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives rear wheels, front wheels engaged via clutch. |
| Number of gears and type of gearbox | 6 gears, automatic transmission Allison |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 373×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 235/80 R17; 265/70 R18 |
Powertrain & Engine Architecture
The heart of this Sierra 3500HD is the 6.6-liter Duramax LML turbo diesel V8 engine. This engine represents a significant evolution of the Duramax design, incorporating a robust cast iron block and aluminum cylinder heads. The LML variant, introduced in 2011, featured a revised combustion chamber, enhanced fuel injection system, and a more efficient turbocharger. The common-rail direct injection system delivers fuel at extremely high pressures, optimizing combustion and maximizing power output. The engine utilizes an overhead valve (OHV) valvetrain, a design choice favored for its durability and low-end torque characteristics. The Allison 1000 six-speed automatic transmission is specifically designed to handle the immense torque produced by the Duramax engine. This transmission features a lock-up torque converter for improved fuel efficiency and a heavy-duty cooling system to prevent overheating under demanding conditions.
Driving Characteristics
The 397 horsepower and 765 lb-ft of torque delivered by the 6.6L Duramax in this configuration provide substantial pulling power. While not as quick as lighter-duty trucks or those equipped with gasoline engines, the Sierra 3500HD excels at towing and hauling heavy loads. The Allison automatic transmission is well-matched to the engine, providing smooth and predictable shifts. The gear ratios are optimized for towing, allowing the truck to maintain speed and control even when carrying a significant payload. Compared to the 1.8L gasoline engine options available in the Sierra 1500, this diesel variant offers a dramatically different driving experience, prioritizing torque and capability over outright acceleration. The automatic transmission, while convenient, does result in a slight reduction in fuel economy compared to a manual transmission equipped model, but the trade-off is increased ease of use, especially in demanding work conditions.
Equipment & Trim Levels
The Crew Cab Standard Box configuration offered a higher level of interior comfort and space compared to extended cab models. Standard features typically included air conditioning, power windows and locks, a basic audio system, and cloth upholstery. The Crew Cab provided ample seating for five passengers. Optional extras included leather upholstery, a premium audio system, navigation, heated seats, and a rear-seat entertainment system. The trim level could vary, with options like SLT and LTZ offering progressively more luxurious appointments. The standard box length provided a good balance between cargo capacity and overall vehicle length.
Chassis & Braking
The Sierra 3500HD features a heavy-duty chassis designed to withstand the stresses of frequent towing and hauling. The front suspension utilizes an independent torsion bar setup with double wishbones, providing a comfortable ride and good handling. The rear suspension employs a traditional leaf spring design, offering robust load-carrying capacity. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power even when heavily loaded. An Anti-lock Braking System (ABS) is standard, enhancing safety and control. The heavy-duty suspension and braking system are crucial for maintaining stability and control when towing trailers or carrying heavy payloads.
Market Reception & Comparison
The 2011-2013 GMC Sierra 3500HD with the 6.6L Duramax and Allison automatic received generally positive reviews. Critics praised its powerful engine, smooth transmission, and impressive towing capacity. Fuel economy, while not exceptional, was considered acceptable for a heavy-duty truck of this size. Compared to the gasoline-powered Sierra 3500HD models, the Duramax diesel offered significantly more torque and better towing performance, but at a higher initial cost. The Duramax also tended to hold its value better in the used car market. Compared to competitors like the Ford Super Duty and Ram 3500, the Sierra 3500HD was often seen as a well-rounded and capable option.
Legacy
The Duramax LML engine and Allison transmission combination has proven to be exceptionally durable and reliable. Properly maintained, these powertrains can easily exceed 200,000 miles. The 2011-2013 Sierra 3500HD remains a popular choice in the used truck market, particularly among buyers seeking a capable and reliable work truck. While newer models offer more advanced features and technology, this generation represents a sweet spot in terms of value and dependability. The LML Duramax is known for its relatively clean emissions system compared to later iterations, making it a desirable option for those concerned about potential repair costs associated with diesel emissions equipment.
