2020 GMC Yukon Fluid Capacities & Specifications

As an ASE-certified master technician, I know that using the correct fluids and lubricants is one of the most critical aspects of vehicle maintenance. Modern vehicles like your 2020 GMC Yukon are built with precise engineering tolerances, and using the wrong fluid—or even the right fluid at the wrong interval—can lead to accelerated wear, poor performance, and costly repairs. This guide will serve as your definitive reference for every factory-spec fluid your Yukon requires.

Quick Reference

This table provides a high-level overview of the fluids your 2020 Yukon needs. Always double-check your owner's manual, especially for capacities, as they can vary slightly based on equipment (e.g., standard vs. high-capacity cooling systems).

Fluid	Type/Spec	Capacity
Engine Oil	0W-20 Synthetic (dexos1® Gen 2)	8.0 quarts (7.6 L)
Engine Coolant	ACDelco Orange DEX-COOL® OAT	14.8 - 17.4 quarts (14.0 - 16.5 L)
Automatic Transmission Fluid	DEXRON® VI Full Synthetic	~6.0 quarts (drain and fill)
Transfer Case Fluid (4WD)	DEXRON® VI Full Synthetic	1.6 quarts (1.5 L)
Front Differential Fluid (4WD)	SAE 75W-90 Synthetic Gear Oil	~1.1 quarts (1.0 L)
Rear Differential Fluid	SAE 75W-90 Synthetic Gear Oil	~2.75 quarts (2.6 L)
Brake Fluid	DOT 3	As needed
Power Steering Fluid	ACDelco Power Steering Fluid	As needed
Windshield Washer Fluid	Good Quality Washer Fluid	~1.0 gallon (3.8 L)

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Engine Oil

For the 5.3L or 6.2L V8 engine in your 2020 Yukon, General Motors specifies a full synthetic oil meeting the dexos1® Gen 2 specification.

• Viscosity: SAE 0W-20
• Specification: dexos1® Gen 2
• Capacity: 8.0 quarts (7.6 liters) with filter change.

Technician's Notes: The dexos1 Gen 2 specification is crucial for modern GM direct-injection engines. It provides superior protection against low-speed pre-ignition (LSPI), a phenomenon that can cause catastrophic piston damage. It also offers enhanced oxidation stability and deposit control. Do not substitute with conventional oils or synthetics that don't carry the official dexos1® logo. Using a heavier weight like 5W-30 can also interfere with the tight tolerances of the engine and its components, such as the variable valve timing (VVT) system.

Engine Coolant (Antifreeze)

The Yukon’s cooling system is filled from the factory with a specific Organic Acid Technology (OAT) coolant.

• Type: DEX-COOL® OAT Antifreeze (Orange)
• Specification: GM 6277M
• Mixture: 50/50 with deionized water.

Technician's Notes: It is a common and costly mistake to mix coolant types. DEX-COOL® is an orange, OAT-based coolant designed for a long service life (up to 5 years or 150,000 miles). Mixing it with traditional green (IAT) or even hybrid (HOAT) coolants can cause it to gel, leading to clogged heater cores, radiators, and catastrophic engine overheating. Never use "universal" or "all makes, all models" coolants. If you are performing a flush, use only DEX-COOL® or a compatible OAT coolant that explicitly meets the GM 6277M spec, and always mix it with distilled or deionized water to prevent mineral deposits.

Automatic Transmission Fluid

Your Yukon is equipped with a 6-speed (6L80) or 10-speed (10L90) automatic transmission that requires a low-viscosity, full synthetic fluid.

• Type: ACDelco DEXRON® VI Full Synthetic ATF
• Specification: DEXRON® VI

Technician's Notes: DEXRON® VI is not backward-compatible with older DEXRON fluids in all applications and you should never use a different type like Mercon or ATF+4. Using the wrong fluid can lead to harsh shifting, transmission shudder, and eventual clutch pack failure. A standard "drain and fill" procedure will only replace about half of the fluid, as much of it remains in the torque converter and cooler lines. For a full exchange, a fluid transfer machine is required.

Drivetrain Fluids (4WD Models)

Transfer Case

The transfer case directs power to the front wheels and requires the same fluid as the transmission.

• Type: DEXRON® VI Full Synthetic ATF
• Capacity: Approximately 1.6 quarts (1.5 L)

Front Differential

• Type: SAE 75W-90 Synthetic Axle Lubricant
• Specification: GM 9986115

Rear Differential

• Type: SAE 75W-90 Synthetic Axle Lubricant
• Specification: GM 9986115

Technician's Notes: Always use a high-quality synthetic gear oil. While some differentials require a limited-slip friction modifier additive, the 2020 Yukon factory service information does not specify one for the standard rear axle. However, if your Yukon is equipped with an aftermarket limited-slip differential (LSD), a friction modifier will be essential. Always check the fill plug before the drain plug to ensure you can refill the differential.

Brake Fluid

The hydraulic brake system requires a specific grade of glycol-based fluid.

• Type: DOT 3 Motor Vehicle Brake Fluid
• Specification: GM 19353126 or equivalent

Technician's Notes: Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. This moisture lowers the fluid's boiling point, which can lead to a soft or spongy pedal and reduced braking effectiveness in hard stops. It also causes internal corrosion in the ABS module, lines, and calipers. For this reason, brake fluid should be flushed and replaced every 2-3 years, regardless of mileage. While DOT 4 fluid has a higher boiling point and is compatible with DOT 3, it is also more hygroscopic and will need to be changed more frequently.

Power Steering Fluid

Unlike many systems that use ATF, GM specifies a dedicated power steering fluid.

• Type: ACDelco Power Steering Fluid
• Specification: GM 9985010

Technician's Notes: Do not use automatic transmission fluid in the power steering system. Using ATF can damage the seals in the steering rack and pump, leading to leaks and expensive repairs. Top off or flush only with a fluid that meets the manufacturer's specification.

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Keeping up with your 2020 GMC Yukon's fluid maintenance is the best way to ensure its longevity, reliability, and performance for years to come. When in doubt, always refer to your owner's manual or consult with a professional.

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