The Chevrolet Silverado 2500 HD IV (T1XX) Double Cab Long Bed, equipped with the 6.6-liter Duramax V8 engine producing 445 horsepower and paired with a 10-speed automatic transmission and four-wheel drive, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2020 to 2023, this configuration occupied a premium position within the fourth generation (T1XX) Silverado 2500/3500 HD lineup, targeting buyers requiring substantial towing and hauling capabilities without sacrificing everyday usability. It was designed to compete directly with offerings from Ford (Super Duty) and Ram (Heavy Duty) in the North American market.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD IV (T1XX) Double Cab Long Bed |
| Type (Engine) | 6.6 Duramax V8 (445 Hp) 4WD Automatic |
| Start of production | 2020 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Diesel |
| Weight-to-power ratio | 7.9 kg/Hp, 127 Hp/tonne |
| Weight-to-torque ratio | 2.8 kg/Nm, 352.1 Nm/tonne |
| Power | 445 Hp @ 2800 rpm |
| Power per litre | 67.4 Hp/l |
| Torque | 1234 Nm @ 1600 rpm (910.15 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Duramax L5P |
| Engine displacement | 6604 cm3 (403 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 | 29.1 l (30.75 US qt | 25.6 UK qt) |
| Kerb Weight | 3505 kg (7727.2 lbs.) |
| Max. weight | 5080 kg (11199.48 lbs.) |
| Max load | 1575 kg (3472.28 lbs.) |
| Trunk (boot) space – maximum | 2364 l (83.48 cu. ft.) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 8051 kg (17749.42 lbs.) |
| Length | 6514 mm (256.46 in.) |
| Width including mirrors | 2079 mm (81.85 in.) |
| Height | 2027 mm (79.8 in.) |
| Wheelbase | 4127 mm (162.48 in.) |
| Front track | 1731 mm (68.15 in.) |
| Rear (Back) track | 1736 mm (68.35 in.) |
| Ride height (ground clearance) | 258 mm (10.16 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 Allison |
Powertrain & Engine Architecture
The heart of this Silverado 2500 HD variant is the Duramax L5P 6.6-liter V8 diesel engine. This engine, a cornerstone of Chevrolet’s heavy-duty lineup for years, utilizes a cast iron block and aluminum cylinder heads. The L5P features a common-rail direct fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) with an intercooler provides increased power and torque across a broad RPM range. The engine employs an overhead valve (OHV) valvetrain, a design choice prioritizing durability and low-end torque. The 10-speed Allison automatic transmission, introduced with the T1XX generation, replaced the previous 6-speed unit. This transmission offers closer gear ratios, improving both acceleration and fuel efficiency, and provides smoother shifting compared to its predecessor. The transmission is electronically controlled and features a tow/haul mode optimized for heavy loads.
Driving Characteristics
The combination of the 445-hp Duramax engine and the 10-speed Allison transmission delivers a compelling driving experience, even in a heavy-duty truck. While not as overtly quick as gasoline-powered alternatives, the Silverado 2500 HD excels in providing substantial, readily available torque. The 1234 Nm (910.15 lb-ft) of torque at 1600 rpm allows for effortless towing and hauling, even with significant payloads. The 10-speed transmission keeps the engine within its optimal power band, minimizing gear hunting and maximizing efficiency. Compared to the 6.6L gasoline V8 option, the Duramax offers significantly more torque and better fuel economy, especially when towing. Compared to lower-output Duramax variants, this 445 hp version provides a noticeable increase in power, making it more confident for demanding tasks. The automatic transmission, while convenient, doesn’t offer the same level of control as a manual transmission, but the tow/haul mode effectively manages gear selection for optimal performance under load.
Equipment & Trim Levels
The 6.6 Duramax/10-speed automatic combination was typically offered on higher trim levels of the Silverado 2500 HD, such as the LT, LTZ, and High Country. Standard features included a comprehensive infotainment system with Apple CarPlay and Android Auto compatibility, a rearview camera, and a suite of safety features like automatic emergency braking. Higher trims added luxury features such as leather upholstery, heated and ventilated seats, a premium sound system, and advanced trailering technologies. Optional extras included a power sunroof, a rear-seat entertainment system, and various appearance packages. The Double Cab configuration provided ample space for passengers, while the Long Bed offered a generous cargo capacity.
Chassis & Braking
The Silverado 2500 HD IV utilizes a fully boxed frame for enhanced rigidity and durability. The front suspension consists of an independent torsion bar setup with double wishbone control arms, while the rear suspension employs a traditional leaf spring configuration. This setup is designed to handle heavy loads and provide a comfortable ride. Braking duties are handled by ventilated disc brakes on all four wheels, with larger rotors and calipers on the front axle. An Anti-lock Braking System (ABS) is standard. The steering system is a hydraulic power-assisted recirculating ball system, providing a robust and reliable feel. Tire sizes varied depending on the trim level and wheel choice, ranging from 265/70R17 to 265/60R20.
Market Reception & Comparison
The 2020-2023 Chevrolet Silverado 2500 HD with the 6.6 Duramax engine and 10-speed automatic received generally positive reviews. Critics praised the engine’s power and torque, the transmission’s smoothness, and the truck’s overall capability. Fuel economy was considered competitive for a heavy-duty diesel truck. However, some reviewers noted that the interior design wasn’t as refined as some competitors, particularly the Ram Heavy Duty. Compared to the gasoline-powered Silverado 2500 HD, the Duramax diesel offered significantly better fuel economy when towing and a much higher towing capacity. Compared to the Ford Super Duty and Ram Heavy Duty, the Silverado 2500 HD was often seen as a strong all-around performer, offering a good balance of capability, comfort, and value.
Legacy
The Duramax L5P engine has proven to be a remarkably durable and reliable powertrain. While diesel engines generally require more maintenance than gasoline engines, the L5P has a strong track record for longevity. In the used car market, Silverado 2500 HD models equipped with this engine and transmission combination command a premium price due to their proven capability and reliability. These trucks remain popular choices for owners who require a robust and dependable workhorse for towing, hauling, and demanding tasks. The introduction of the 10-speed Allison transmission further enhanced the powertrain’s reputation, providing a smoother and more efficient driving experience.
