2021 Chevrolet Tahoe Fluid Capacity and Specifications

As an ASE-certified master technician, I know that using the correct fluids and lubricants is non-negotiable for the longevity and performance of your vehicle. This guide details all the factory-specified fluids and capacities for the 2021 Chevrolet Tahoe. Using the right products will protect your warranty and help you avoid costly repairs down the road.

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil (5.3L V8 L84)	0W-20, dexos1 Gen 2 or Gen 3	8.0 quarts (7.6 liters)
Engine Oil (6.2L V8 L87)	0W-20, dexos1 Gen 2 or Gen 3	8.0 quarts (7.6 liters)
Engine Oil (3.0L I6 LM2 Diesel)	0W-20, dexosD	7.0 quarts (6.6 liters)
Engine Coolant	DEX-COOL (Orange, OAT)	14.5–18.3 quarts (13.7–17.3 liters)
Automatic Transmission (10-speed)	DEXRON ULV (ACDelco 19417577)	11.4 quarts (10.8 liters) for service fill
Transfer Case (Autotrac 2-speed)	DEXRON VI	2.1 pints (1.0 liter)
Front Differential	75W-85 GL-5 Gear Oil (ACDelco 19375171)	2.3 pints (1.1 liters)
Rear Differential	75W-85 GL-5 Gear Oil (ACDelco 19375171)	3.6 pints (1.7 liters)
Brake Fluid	DOT 4	As needed
Power Steering	N/A (Electric Power Steering)	N/A
Washer Fluid	Good quality solvent	~1.0 gallon (3.8 liters)
Diesel Exhaust Fluid (DEF)	API Certified ISO 22241	5.0 gallons (18.9 liters)

Engine Oil

The 2021 Tahoe offers three engine choices, each with a specific oil requirement. Using the wrong oil can lead to reduced fuel economy, increased emissions, and premature engine wear.

• 5.3L V8 (L84) & 6.2L V8 (L87): These gasoline engines require a full synthetic SAE 0W-20 motor oil that meets GM dexos1 Gen 2 or the superseding Gen 3 specification. The API "starburst" symbol on the bottle should indicate API SP. Capacity with a new filter is 8.0 quarts (7.6 liters).
• 3.0L Duramax I6 (LM2) Diesel: The diesel engine has unique needs and requires a specific diesel-rated oil. Use SAE 0W-20 that meets the GM dexosD specification. Do not use gasoline engine oil in the Duramax. Capacity with a filter change is 7.0 quarts (6.6 liters).

Note: Always verify the specification on the bottle. Using a non-licensed product can void your powertrain warranty.

Engine Coolant (Antifreeze)

The cooling system in your Tahoe is filled from the factory with ACDelco DEX-COOL Antifreeze/Coolant. This is an orange-colored, silicate-free and phosphate-free Organic Acid Technology (OAT) coolant.

• Specification: GM 6277M
• Mixture: 50/50 with deionized water.
• Interval: 5 years or 150,000 miles, whichever comes first.

Pitfall: Never mix DEX-COOL with other coolant types, especially older green or yellow Inorganic Acid Technology (IAT) or Hybrid OAT (HOAT) fluids. Mixing them can cause the coolant to gel, leading to blockages, overheating, and significant damage to the radiator, water pump, and heater core.

Automatic Transmission Fluid

All 2021 Tahoes are equipped with a 10-speed automatic transmission. This advanced transmission requires a very specific, low-viscosity fluid to function correctly.

• Specification: DEXRON ULV (Ultra-Low Viscosity).
• OEM Part Number: ACDelco 19417577.

This is not a "universal" or multi-vehicle fluid. Using standard DEXRON VI or any other ATF will cause severe drivability issues and can lead to catastrophic transmission failure. Always insist on the exact ULV fluid. A complete fluid exchange is complex; a typical pan-drop service fill is around 11.4 quarts.

Drivetrain Fluids

Properly servicing the 4WD system and differentials is critical for traction and preventing expensive gear failures.

Transfer Case

For models equipped with the Autotrac 2-speed transfer case, the required fluid is DEXRON VI Automatic Transmission Fluid.

• Capacity: Approximately 2.1 pints (1.0 liter).

Front and Rear Differentials

Both the front and rear axles use a high-quality synthetic gear oil.

• Specification: SAE 75W-85 GL-5 gear lubricant.
• OEM Part Number: ACDelco 19375171.
• Capacities:
  • Front Differential: 2.3 pints (1.1 liters)
  • Rear Differential: 3.6 pints (1.7 liters)

If your Tahoe is equipped with the electronic limited-slip differential (eLSD), no special friction modifier additive is required as the OEM fluid already contains the necessary formulation.

Brake Fluid

GM specifies DOT 4 brake fluid for the 2021 Tahoe. While DOT 3 is technically compatible in an emergency, it has a lower boiling point and does not provide the same level of performance and safety margin as DOT 4.

• Interval: Check fluid level at every service and replace every 3 to 5 years, or as indicated by testing.
• Pitfall: Brake fluid is hygroscopic, meaning it absorbs moisture from the air. This moisture lowers the boiling point, which can lead to a soft or spongy pedal and reduced braking effectiveness in demanding situations.

Power Steering

The 2021 Tahoe uses an Electric Power Steering (EPS) system. It does not have a hydraulic pump, reservoir, or fluid to check or change.

Washer Fluid

Use any good-quality automotive windshield washer solvent. In colder climates, ensure the fluid has an appropriate freeze protection rating to prevent freezing in the reservoir or on the windshield.

Diesel Exhaust Fluid (DEF)

For Tahoes with the 3.0L Duramax diesel engine, maintaining the DEF level is mandatory for the vehicle to run. The system injects this fluid into the exhaust to reduce harmful nitrogen oxide emissions.

• Specification: Use a high-quality DEF that is API Certified and meets the ISO 22241 standard.
• Tank Capacity: 5.0 gallons (18.9 liters).
• Note: The dashboard will provide ample warning before the DEF tank runs empty. If you allow it to run completely dry, the vehicle will enter a reduced power mode and eventually will not restart until the tank is refilled.

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