2019 GMC Yukon Transmission Fluid & Service Spec

Quick Answer

• Transmission Make/Model: GM 8L90 (RPO M5U)
• OEM Fluid Spec: ACDelco DEXRON ULV Automatic Transmission Fluid
• Drain & Fill Capacity: Approximately 7.0 - 8.0 quarts (6.6 - 7.6 liters)
• Full Overhaul Capacity: Approximately 11.4 quarts (10.8 liters)
• Filter OEM Part Number: Verify with dealer or service manual (typically ACDelco 24278401 or equivalent)
• Recommended Service Interval:
  • Normal Duty: 97,500 miles (150,000 km)
  • Severe Duty / Towing: 45,000 miles (72,000 km)

Fluid Type Explained

The 2019 GMC Yukon, when equipped with the 8L90 (RPO M5U) 8-speed automatic transmission, requires a very specific fluid type: ACDelco DEXRON ULV Automatic Transmission Fluid. ULV stands for "Ultra Low Viscosity," and this is crucial. This fluid is specially formulated for modern, highly efficient transmissions like the 8L90, which operate with tighter tolerances and specific friction characteristics. Using any other fluid, such as standard DEXRON VI or older DEXRON types, can lead to serious transmission issues, including shudder, harsh shifts, and premature wear. The wrong fluid can compromise the performance of internal components, such as clutch packs and solenoids, which are designed to operate with the specific lubricating and friction properties of DEXRON ULV.

Always ensure that any fluid used meets the DEXRON ULV specification. Even major aftermarket brands will clearly state if their fluid is compatible with DEXRON ULV requirements. When in doubt, always opt for the ACDelco OEM fluid to guarantee compatibility and optimal performance for your 8L90 transmission.

Service Procedure: Drain & Fill vs. Full Exchange

Servicing your 2019 GMC Yukon's 8L90 transmission can be done via two primary methods: a drain and fill or a full fluid exchange (flush).

Drain & Fill

A drain and fill involves removing the transmission pan, allowing approximately 7.0 - 8.0 quarts of old fluid to drain out, replacing the filter, and then refilling with fresh DEXRON ULV fluid. This method is simpler, less expensive, and is what many manufacturers recommend for routine maintenance. The downside is that it only replaces a portion of the total transmission fluid. A significant amount of old fluid remains in the torque converter, valve body, and cooler lines. For this reason, some technicians recommend performing multiple drain and fills over time to gradually dilute the old fluid with new.

Typical Procedure:

1. Raise the vehicle and support it safely.
2. Place a drain pan under the transmission.
3. Remove the transmission drain plug (if equipped) or carefully loosen the pan bolts to drain fluid.
4. Remove the transmission pan.
5. Remove and replace the transmission filter. Verify the correct OEM part number with your dealer or service manual, but it is typically ACDelco 24278401 or an equivalent.
6. Clean the transmission pan and magnet(s). Replace the pan gasket if necessary.
7. Reinstall the pan.
8. Refill with the specified amount of ACDelco DEXRON ULV fluid through the fill plug/tube until the correct level is achieved according to the service manual