2020 Chevrolet Silverado 2500HD Fluid Type Specifications Guide

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (Gas L8T 6.6L)	SAE 0W-20, dexos1 Gen2 (or newer)	~8.0 quarts
Engine Oil (Diesel L5P 6.6L Duramax)	SAE 5W-40 or 15W-40, dexos2 or API CK-4	~10.0 quarts
Engine Coolant	Dex-Cool (Orange/Red), OAT, GM6277M	~16-17 quarts
Transmission Fluid (10-speed Allison)	Dexron ULV	~14.0 - 15.0 quarts (drain/fill)
Transfer Case (AutoTrac/NVG 261/263/271/273)	AutoTrak II (Blue) or Dexron HP	~2.0 quarts
Front Differential	SAE 75W-90 Synthetic, GM Spec 9986115	~1.8 quarts
Rear Differential (10.5" AAM)	SAE 75W-90 Synthetic, GM Spec 9986115 (with friction modifier if G80 LSD)	~2.75 quarts
Rear Differential (11.5" AAM)	SAE 75W-90 Synthetic, GM Spec 9986115 (with friction modifier if G80 LSD)	~3.7 - 4.2 quarts
Brake Fluid	DOT 3 or DOT 4	As needed
Power Steering Fluid	Dexron VI ATF	As needed
Washer Fluid	GM Optikleen or equivalent all-season washer fluid	~1 gallon
Diesel Exhaust Fluid (DEF)	ISO 22241 (API DEF)	~7.0 gallons

Engine Oil

Gasoline Engine (6.6L L8T V8): The 2020 Chevrolet Silverado 2500HD with the 6.6L L8T gasoline engine requires SAE 0W-20 synthetic motor oil. It is crucial to use oil meeting the GM dexos1 Gen2 specification or a newer generation (e.g., dexos1 Gen3). Using an oil that does not meet this specification can lead to reduced engine performance, increased wear, and potential damage, including low-speed pre-ignition (LSPI) in modern direct-injection engines. The typical capacity for an oil change is approximately 8.0 quarts with a filter change.

Diesel Engine (6.6L L5P Duramax): For the 6.6L L5P Duramax diesel engine, the recommended engine oil is SAE 5W-40 or 15W-40 full synthetic diesel engine oil. This oil must meet GM dexos2 specification or API CK-4. API CK-4 oils are specifically designed for high-speed four-stroke diesel engines and are formulated to provide improved shear stability, oxidation resistance, and aeration control. The oil capacity for the Duramax engine is around 10.0 quarts with a filter change.

Intervals and Pitfalls: Always follow the Oil Life Monitoring (OLM) system in your vehicle for oil change intervals. Typically, this can range from 7,500 to 12,000 miles or once a year, whichever comes first, depending on driving conditions. Neglecting the OLM can lead to premature engine wear. It's vital to use full synthetic oil for both gasoline and diesel engines to ensure optimal performance and protection.

Engine Coolant

The 2020 Silverado 2500HD uses a long-life Organic Acid Technology (OAT) coolant, specifically GM Dex-Cool. This coolant is typically orange or red in color and meets the GM6277M specification. Dex-Cool is designed to provide extended protection against corrosion and cavitation for up to 5 years or 150,000 miles, whichever comes first.

Intervals and Pitfalls: Never mix Dex-Cool with conventional (silicate-based) coolants or Hybrid Organic Acid Technology (HOAT) coolants, as this can lead to gel formation, reduce the coolant's effectiveness, and potentially cause severe damage to the cooling system and engine. Always use distilled water if mixing concentrate, though pre-mixed 50/50 solutions are recommended for convenience and purity.

Transmission Fluid

The 2020 Silverado 2500HD utilizes the robust 10-speed Allison automatic transmission. This transmission requires Dexron ULV (Ultra Low Viscosity) automatic transmission fluid. It is critical to use only Dexron ULV, as other Dexron specifications (like Dexron VI) are not compatible and can lead to transmission damage due to incorrect viscosity and additive packages. A typical drain and fill will require approximately 14.0 - 15.0 quarts.

Intervals and Pitfalls: Transmission fluid change intervals can vary significantly based on usage, especially if the vehicle is used for heavy towing or hauling. Consult your owner's manual for specific maintenance schedules. Using a universal ATF or an incorrect Dexron fluid is a common and costly mistake that can lead to premature transmission failure.

Transfer Case Fluid

For models equipped with 4WD or AWD, the transfer case typically requires AutoTrak II (blue in color) fluid for the AutoTrac systems or Dexron HP for other heavy-duty transfer cases (like the NVG 261/263/271/273). The capacity is around 2.0 quarts. Always verify the exact fluid type in your owner's manual as transfer cases can vary by trim and package.

Intervals and Pitfalls: Transfer case fluid changes are generally recommended every 50,000 to 100,000 miles, or more frequently with heavy use. Using an incorrect fluid type can lead to binding, noise, and premature wear of the transfer case components.

Differential Fluid (Front & Rear)

Both the front and rear differentials in the 2020 Silverado 2500HD typically specify SAE 75W-90 Synthetic Gear Oil meeting GM Spec 9986115.

Front Differential: Approximately 1.8 quarts.

Rear Differential: The capacity varies based on the differential size. For the 10.5-inch AAM rear differential, it's about 2.75 quarts. For the larger 11.5-inch AAM rear differential, the capacity is roughly 3.7 - 4.2 quarts. If your vehicle is equipped with a limited-slip differential (G80 RPO code), a friction modifier additive may be required in conjunction with the gear oil to ensure proper operation and prevent chatter. Always check your owner's manual regarding the need for a friction modifier.

Intervals and Pitfalls: Differential fluid should generally be changed every 50,000 miles under normal conditions, or more often if the vehicle is frequently used for towing, off-roading, or in dusty environments. Neglecting differential fluid changes can lead to premature wear of gears and bearings due to contaminated or degraded oil.

Brake Fluid

The 2020 Chevrolet Silverado 2500HD uses standard DOT 3 or DOT 4 brake fluid. DOT 4 has a higher boiling point than DOT 3, offering better performance under heavy braking or demanding conditions. You can generally upgrade from DOT 3 to DOT 4, but never use DOT 5 (silicone-based) fluid, as it is incompatible with systems designed for DOT 3/4 and can cause seal damage.

Intervals and Pitfalls: Brake fluid is hygroscopic, meaning it absorbs moisture over time, which lowers its boiling point and can lead to corrosion in the brake system. It is generally recommended to flush and replace brake fluid every 2-3 years, regardless of mileage, to maintain optimal braking performance and longevity of brake components.

Power Steering Fluid

The 2020 Silverado 2500HD with its hydraulic power steering system requires Dexron VI Automatic Transmission Fluid for its power steering system. While it's an ATF, it's specified for power steering in this application. Do not use conventional power steering fluid.

Intervals and Pitfalls: Power steering fluid typically does not have a strict replacement interval but should be checked for color and contamination. If the fluid appears dark or smells burnt, it's a good indication that it needs to be flushed and replaced. Using the wrong type of fluid can cause pump whine, hard steering, and eventual component failure.

Washer Fluid

Any high-quality, all-season windshield washer fluid will suffice for the 2020 Silverado 2500HD. GM often recommends GM Optikleen or an equivalent. Using a fluid with de-icing properties is beneficial in colder climates. Capacity is approximately 1 gallon.

Diesel Exhaust Fluid (DEF)

For the Duramax diesel equipped Silverado 2500HD, Diesel Exhaust Fluid (DEF) is essential for the Selective Catalytic Reduction (SCR) system to reduce NOx emissions. DEF must meet the ISO 22241 standard, which is also sometimes referred to as API DEF. The DEF tank capacity is approximately 7.0 gallons.

Intervals and Pitfalls: DEF consumption is dependent on driving conditions and engine load. The vehicle's onboard computer will provide warnings when DEF levels are low. It is crucial to use only high-quality DEF that meets the ISO 22241 standard. Never put DEF in the diesel fuel tank or vice-versa, as this will cause severe and costly damage to the engine and emissions system. Store DEF in a cool, dry place and be mindful of its shelf life, which is typically 1-2 years.

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