2024 GMC Sierra 2500HD Fluid Type Specifications

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil
6.6L L8T Gasoline	SAE 0W-20, dexosD (GM dexos1 Gen3 compatible)	8.0 quarts (7.6 liters) with filter
6.6L L5P Duramax	SAE 15W-40, API CK-4 (or CJ-4), dexosD (low ash)	10.0 quarts (9.5 liters) with filter
Engine Coolant	DEX-COOL® (GM Spec 6277M) Orange/Red OAT	16.0–17.0 quarts (15.1–16.1 liters) (approx)
Transmission
10-speed Automatic	DEXRON® ULV (GM Spec 10L90)	13.0 quarts (12.3 liters) (approx)
Transfer Case	AutoTrak II Fluid (GM Spec 9986326)	2.0 quarts (1.9 liters) (approx)
Front Diff	SAE 75W-90 Synthetic Hypoid Gear Oil (GM Spec 9986153)	1.7 quarts (1.6 liters) (approx)
Rear Diff	SAE 75W-90 Synthetic Hypoid Gear Oil (GM Spec 9986153)	3.0-3.5 quarts (2.8-3.3 liters) (approx)
	(For models with locking/limited-slip, add Friction Modifier)
Brake Fluid	DOT 3 or DOT 4 Heavy Duty Brake Fluid	As needed
Power Steering	DEXRON® VI Automatic Transmission Fluid	As needed
Washer Fluid	GM Optikleen® Washer Solvent (or equivalent)	1.0 gallon (3.8 liters) (approx)
DEF	ISO 22241 / API DEF certified	7.0 gallons (26.5 liters) (approx)

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Engine Oil

6.6L L8T Gasoline Engine:

For the 2024 GMC Sierra 2500HD equipped with the 6.6L L8T gasoline engine, the factory-recommended engine oil is an SAE 0W-20 viscosity grade. It is critical to use an oil that meets or exceeds the dexosD specification. While dexosD is a newer GM specification primarily for gasoline direct injection engines, oils meeting the GM dexos1 Gen3 standard are generally suitable as they are formulated to provide enhanced protection against low-speed pre-ignition (LSPI), timing chain wear, and turbocharger coking. Always refer to your owner's manual for the most up-to-date and specific dexosD requirements. The oil capacity for this engine is approximately 8.0 quarts (7.6 liters) with a new filter.

6.6L L5P Duramax Diesel Engine:

For the 6.6L L5P Duramax diesel engine, the recommended engine oil is an SAE 15W-40. It must meet the API CK-4 specification, which is designed for high-speed four-stroke diesel engines and offers improved oxidation resistance, shear stability, and aeration control. Oils meeting the previous API CJ-4 specification may also be acceptable, but CK-4 is preferred for optimal protection. Additionally, the oil must meet the dexosD specification which is a low-ash formulation specifically for diesel engines equipped with modern emission control systems like Diesel Particulate Filters (DPFs). Using an oil that does not meet the low-ash requirement can contaminate and damage your DPF, leading to costly repairs. The oil capacity for the Duramax is approximately 10.0 quarts (9.5 liters) with a new filter. Adherence to oil change intervals, typically found in the owner's manual or through the vehicle's Oil Life Monitoring system, is crucial for engine longevity.

Engine Coolant

The 2024 GMC Sierra 2500HD utilizes DEX-COOL® engine coolant, which is an Organic Acid Technology (OAT) formulation. This coolant is typically identifiable by its orange/red color and meets GM Specification 6277M. It offers extended service life, usually up to 5 years or 150,000 miles, whichever comes first. It is vital to use only DEX-COOL® or a compatible OAT coolant that meets the GM 6277M spec. Never mix DEX-COOL® with traditional green inorganic acid technology (IAT) coolants or hybrid organic acid technology (HOAT) coolants, as this can lead to chemical incompatibilities, gel formation, reduced corrosion protection, and potential damage to the cooling system components. Always dilute concentrated coolant with distilled water to the manufacturer's recommended ratio, typically 50/50, to ensure proper freeze protection and heat transfer. The approximate cooling system capacity is 16.0–17.0 quarts (15.1–16.1 liters).

Transmission Fluid

The 2024 GMC Sierra 2500HD, equipped with the 10-speed automatic transmission, requires DEXRON® ULV (Ultra Low Viscosity) automatic transmission fluid. This fluid is specifically engineered for enhanced fuel efficiency and performance in modern multi-speed transmissions. It meets GM Specification 10L90. It is imperative to use only DEXRON® ULV and never substitute it with older DEXRON® VI, DEXRON® III, or any "universal" ATF. Using the incorrect fluid can lead to premature transmission wear, shuddering, shifting issues, and eventual transmission failure. Transmission fluid changes are generally not required under normal driving conditions for the life of the vehicle, but severe duty cycles (towing, heavy hauling, frequent off-road use) may necessitate earlier service intervals. Consult your owner's manual for specific maintenance schedules. The approximate fill capacity is 13.0 quarts (12.3 liters) during a drain and refill, though a complete overhaul may require more.

Transfer Case Fluid

For 4WD and AWD models of the 2024 GMC Sierra 2500HD, the transfer case typically requires AutoTrak II Fluid, which meets GM Specification 9986326. This is a specialized fluid formulated for electronic shift transfer cases to ensure smooth operation and proper engagement of the different driving modes. Never use generic gear oil or other types of automatic transmission fluid in the transfer case. Using the wrong fluid can cause damage to the internal clutch packs and other components. The approximate capacity is 2.0 quarts (1.9 liters). Check your owner's manual for specific service intervals, especially if you frequently engage in heavy towing or off-road use.

Differential Fluid

Front and Rear Differentials:

Both the front and rear differentials on the 2024 GMC Sierra 2500HD generally require SAE 75W-90 Synthetic Hypoid Gear Oil. This fluid meets GM Specification 9986153. Synthetic gear oils offer superior thermal stability and wear protection, especially under heavy load conditions common in a 2500HD truck. The approximate capacity for the front differential is 1.7 quarts (1.6 liters), and for the rear differential, it is typically around 3.0-3.5 quarts (2.8-3.3 liters), though this can vary slightly based on axle size and setup. It is always best to verify the exact capacity in your owner's manual or OEM service information.

Limited-Slip / Locking Differentials:

If your Sierra 2500HD is equipped with a limited-slip or Eaton G80 automatic locking rear differential, it is crucial to verify if a friction modifier additive is required. While many modern synthetic gear oils are pre-formulated with friction modifiers, some differential designs may still require an additional additive to prevent chatter and ensure smooth operation of the clutch packs. Refer to your owner's manual or the differential cover tag for specific instructions. Failure to use the correct fluid or additive can lead to noise and accelerated wear in limited-slip differentials.

Brake Fluid

The 2024 GMC Sierra 2500HD uses a hydraulic brake system requiring either DOT 3 or DOT 4 Heavy Duty Brake Fluid. While both are glycol-ether based and compatible, DOT 4 has a higher boiling point, providing a greater margin of safety, especially under severe braking conditions or heavy loads. Never use DOT 5 (silicone-based) brake fluid, as it is not compatible with systems designed for DOT 3 or DOT 4 and can cause seal damage and brake failure. 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, or as specified in your owner's manual, regardless of mileage.

Power Steering Fluid

For models equipped with traditional hydraulic power steering (some models may use electric power steering, which requires no fluid service), the 2024 GMC Sierra 2500HD typically uses DEXRON® VI Automatic Transmission Fluid as its power steering fluid. While it might seem counterintuitive to use ATF in a power steering system, many modern GM vehicles are designed for it. Check your power steering reservoir cap for the exact fluid recommendation. Never use older DEXRON® III or generic power steering fluids unless explicitly stated in your owner's manual. The capacity is "as needed" to maintain the proper level between the MIN and MAX marks on the reservoir.

Washer Fluid

The windshield washer system on the 2024 GMC Sierra 2500HD requires a high-quality automotive windshield washer solvent. GM Optikleen® Washer Solvent or an equivalent product is recommended. For cold climates, ensure the fluid has adequate freeze protection (rated for temperatures well below freezing) to prevent the fluid from freezing in the reservoir, lines, or nozzles. Avoid using plain water, as it offers no cleaning agents and will freeze in cold weather. The approximate capacity of the washer fluid reservoir is 1.0 gallon (3.8 liters).

Diesel Exhaust Fluid (DEF)

For 2024 GMC Sierra 2500HD models equipped with the 6.6L L5P Duramax diesel engine, Diesel Exhaust Fluid (DEF) is essential for the Selective Catalytic Reduction (SCR) system, which reduces nitrogen oxide (NOx) emissions. DEF must meet the ISO 22241 standard and be API DEF certified. This ensures the fluid is of the correct purity and concentration (32.5% urea solution) required for proper SCR system operation. Never use any other fluid, such as coolant, fuel, or water, in the DEF tank, as this will cause severe damage to the SCR system. The DEF tank typically has an approximate capacity of 7.0 gallons (26.5 liters). AdBlue is a commonly recognized brand of DEF that meets these specifications. Store DEF in a cool, dry place and ensure it does not freeze, as repeated freezing and thawing can degrade its effectiveness. The vehicle's instrument cluster will provide warnings when the DEF level is low.

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