2023 Chevrolet Silverado 2500HD Fluid Specs

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil (6.6L Gas L8T)	0W-40 or 5W-40 dexosR Full Synthetic	8.0 quarts (7.6L)
Engine Oil (6.6L Diesel L5P)	15W-40 or 5W-40 API CK-4	10.0 quarts (9.5L)
Engine Coolant	DEX-COOL OAT (Orange)	20.3 - 24.5 quarts (19.2 - 23.2L)
Automatic Transmission Fluid	DEXRON ULV Automatic Transmission Fluid	~19.6 quarts (18.5L)
Transfer Case Fluid	DEXRON VI Automatic Transmission Fluid	~1.6 quarts (1.5L)
Front Differential (4WD)	SAE 75W-90 Synthetic Gear Oil	~1.8 quarts (1.7L)
Rear Differential	SAE 75W-90 Synthetic Gear Oil	~3.0 quarts (2.8L)
Brake Fluid	DOT 4	As needed
Power Steering Fluid	DEXRON VI Automatic Transmission Fluid	As needed
Windshield Washer Fluid	Good Quality Washer Fluid	~1.1 gallons (4.2L)
Diesel Exhaust Fluid (DEF)	ISO 22241	7.2 gallons (27.2L)

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Engine Oil

6.6L V8 L8T (Gasoline): The gasoline engine requires a full synthetic 0W-40 or 5W-40 engine oil that meets GM dexosR specification. This new specification is backward-compatible with older dexos1 and dexos2 specs but is specifically formulated for the demands of modern GM gasoline engines. Using a dexosR oil ensures proper performance, protection, and fuel economy. The oil capacity is 8.0 quarts (7.6 liters) with a filter change.

6.6L V8 L5P Duramax (Diesel): For the powerhouse Duramax diesel, use a high-quality diesel engine oil meeting API Service CK-4. The recommended viscosities are 15W-40 for most operating temperatures, or 5W-40 for improved cold-weather starting. Always look for the API CK-4 donut on the bottle. Capacity with a filter change is 10.0 quarts (9.5 liters).

Note: Always use a high-quality oil filter, like the ACDelco PF66 for the diesel or PF64 for the gasoline engine, during each oil change. Regular oil changes are critical for engine longevity, especially under heavy towing or hauling conditions.

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Engine Coolant

All 2023 Silverado 2500HD models use GM DEX-COOL engine coolant. This is an Organic Acid Technology (OAT) coolant, recognizable by its distinct orange color. It is crucial not to mix DEX-COOL with other coolant types, such as conventional green (IAT) or hybrid (HOAT) coolants, as this can cause gelling and severely damage the cooling system.

The system capacity ranges from 20.3 to 24.5 quarts (19.2 to 23.2 liters) depending on the engine and options. When topping off or refilling, use a pre-mixed 50/50 solution of DEX-COOL and deionized water to maintain the proper freeze and boiling protection.

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Transmission Fluid

The 2023 Silverado 2500HD is equipped with the Allison 10-speed automatic transmission. This advanced transmission requires a very specific fluid: DEXRON ULV (Ultra-Low Viscosity) Automatic Transmission Fluid. Do not use older DEXRON III/VI, Mercon, ATF+4, or any "universal" ATF. Using the incorrect fluid will lead to poor shifting, overheating, and eventual transmission failure. A full system service can require up to 19.6 quarts (18.5 liters), though a pan-drop service will use less. Check the level according to the owner's manual procedure, as there is no traditional dipstick.

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Drivetrain Fluids

Transfer Case (4WD Models): The transfer case requires DEXRON VI (Dex 6) Automatic Transmission Fluid. Note that this is a different specification than the transmission itself. Do not use ULV fluid in the transfer case. Capacity is approximately 1.6 quarts (1.5 liters).

Front Differential: The front axle on 4WD models uses SAE 75W-90 Synthetic Gear Oil. No special friction modifiers are required. Capacity is approximately 1.8 quarts (1.7 liters).

Rear Differential: The rear axle also specifies SAE 75W-90 Synthetic Gear Oil. Even for models equipped with the G80 automatic locking differential, no additional friction modifier additive is needed. The locking mechanism is self-contained and does not rely on fluid additives. Capacity is approximately 3.0 quarts (2.8 liters).

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Brake & Power Steering Fluid

Brake Fluid: The hydraulic brake system requires DOT 4 motor vehicle brake fluid. While DOT 3 is technically compatible in an emergency, DOT 4 has a higher boiling point and is the specified fluid for optimal braking performance, especially when towing. Never use DOT 5 silicone-based fluid. The system should be bled and the fluid replaced every 2-3 years to prevent moisture contamination.

Power Steering: The hydraulic power steering system in the 2500HD uses DEXRON VI (Dex 6) Automatic Transmission Fluid. This is the same fluid used in the transfer case. Keep the reservoir topped off to the appropriate mark.

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Other Fluids

Windshield Washer Fluid: Use any good quality, solvent-based windshield washer fluid. For winter use, select a fluid with a low freezing point to prevent damage to the reservoir and lines. The reservoir holds approximately 1.1 gallons (4.2 liters).

Diesel Exhaust Fluid (DEF) (L5P Duramax): Diesel models require Diesel Exhaust Fluid (DEF) to meet emissions standards. Look for fluid that is API certified and meets the ISO 22241 standard. Using old or contaminated DEF can damage the expensive SCR (Selective Catalytic Reduction) system. The DEF tank holds 7.2 gallons (27.2 liters).

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