If the transmission fluid level is low, not only will you notice erratic shifting, slipping, delayed shifts and banging into gear, but low transmission fluid can cause premature component wear.

In this guide, you will find instructions on how to check the transmission fluid level on the nine-speed GM automatic transmission used on many 2018 and newer Buick, Cadillac, Chevrolet, and GMC vehicles. Also known as 9T45, 9T50, 9T60, and the 9T65 transmissions.

The following procedure should only be carried out if you know that at least some transmission fluid is present. If there is no transmission fluid in the transmission pan, checking the transmission fluid level using these steps can damage the transmission.

How to check transmission fluid level on GM 9-speed automatic transmission

  1. Drive the vehicle for 10 min to allow the transmission fluid to warm up. The transmission fluid level must be checked when the transmission fluid temperature (TFT) is 85– 95°C (185–203°F). Driving for 10 to 15 minutes will put the transmission fluid temperature in the required range. The transmission fluid temperature should be checked with a GM Transmission OBD-II Scanner.
  2. Keep the engine running and let it idle.
  3. Press the brake pedal and move the shifter between Park, Reverse, Neutral, and Drive, keeping the transmission in each gear for at least 5 seconds. Once you have cycled the transmission through PRND, place the transmission in Park.
  4. Raise the vehicle on a lift. The engine needs to stay running in Park and must be level.  If you check the transmission fluid level at home, you must jack up the vehicle at all four jack points and secure each corner with jack stands.
  5. Remove the plastic panel under the transmission.
  6. Remove the transmission fluid set plug on the side of the transmission.
    The transmission fluid level is normal if you notice very little fluid coming out.
    If you notice a lot of transmission fluid flowing out, the transmission is overfilled. Allow excessive fluid to drain.
    If no transmission fluid comes out of the set plug, the transmission fluid level is too low. Add transmission fluid.
  7. If there is no transmission fluid coming out of the set plug hole, you must add transmission fluid. The level is correct when the oil drips out of the set plug hole. The GM units require Dexron 6 fluid.
  8. Once the transmission fluid level has been corrected, reinstall the set plug and cover and lower the vehicle.
  9. Take the vehicle for a test drive. If necessary, carry out Transmission Service Adaptation (Fast Learn)  Procedure. For this procedure, you will need a GM Transmission OBD-II Scanner.

Pay attention to the color of the transmission fluid color. If the transmission fluid is in good condition, it should be red or slightly brown.

If the transmission fluid level is a very dark color or black and smells burned, it could indicate a transmission problem. The transmission fluid looks milky or white, which means engine coolant contamination.

These instructions apply to several GM vehicles equipped with 9T45, 9T50, 9T60, and the 9T65 transmission. See the application below.

Applications

  • 2018+ Buick Enclave
  • 2020+ Cadillac XT5
  • 2020+ Cadillac XT6
  • 2019+ Chevrolet Blazer
  • 2018+ Chevrolet Traverse
  • 2020+ GMC Acadia

GM 9 Speed Transmission Problems

We have noticed a common issue with the 9T65 transmission problem: erratic shifting when the transition is cold. Rough shifting can occur, especially in the 1-2 upshift. This may happen when the transmission is in manual mode as well. This issue can occur on early production 9T65 transmissions. This problem can be due to an undersized 9T65 spacer plate orifice between the 9T65 valve body and transmission case. This problem can trigger the check engine light as well.

Learn how to troubleshoot GM transmission problems.

Fault Codes

The following diagnostic trouble codes may be present in the TCM when a problem is detected.

  • • P0721 Output Speed Sensor Performance
  • • P0722 Output Speed Sensor Circuit No Signal
  • • P0723 Output Speed Sensor Circuit Intermittent
  • • P0741 Torque Converter Clutch (TCC) System Stuck Off
  • • P0746 Transmission Control Solenoid Valve 1 Stuck Off
  • P0747 Transmission Control Solenoid Valve 1 Stuck On
  • • P0776 Transmission Control Solenoid Valve 2 Stuck Off
  • • P0777 Transmission Control Solenoid Valve 2 Stuck On
  • • P0796 Transmission Control Solenoid Valve 3 Stuck Off
  • • P0797 Transmission Control Solenoid Valve 3 Stuck On
  • • P2714 Transmission Control Solenoid Valve 4 Stuck Off
  • • P2715 Transmission Control Solenoid Valve 4 Stuck On
  • • P2723 Transmission Control Solenoid Valve 5 Stuck Off
  • • P2724 Transmission Control Solenoid Valve 5 Stuck On
  • • P2731 Transmission Control Solenoid Valve 6 Performance
  • • P2732 Transmission Control Solenoid Valve 6 Stuck Off
  • • P2733 Transmission Control Solenoid Valve 6 Stuck On
  • • P2817 Transmission Control Solenoid Valve 8 Stuck Off
  • • P2818 Transmission Control Solenoid Valve 8 Stuck On
  • • P2820 Transmission Control Solenoid Valve 9 Stuck Off
  • • P2821 Transmission Control Solenoid Valve 9 Stuck On
  • • P187D Transmission Park Valve Stuck On
  • • P187E Transmission Park Valve Stuck Off
  • • P18E7 Transmission Park Valve Position Sensor 1 Performance
  • • P18E8 Transmission Park Valve Position Sensor 2 Performance
  • • P18AA Transmission Range Control Valve 1 Position Switch Circuit Stuck On
  • • P18AB Transmission Range Control Valve 1 Position Switch Circuit Stuck Off
  • • P18AC Transmission Range Control Valve 2 Position Switch Circuit Stuck On
  • • P18AD Transmission Range Control Valve 2 Position Switch Circuit Stuck Off
  • • P18AE Transmission Range Control Enable Valve Stuck Off
  • • P18A8 Transmission Park Control Solenoid Actuator Stuck Off
  • • P27EC Transmission Range Control Valve 1 Position Switch Performance
  • • P27F0 Transmission Range Control Valve 2 Position Switch Performance

Resources

  1. 9T65 Automatic Transmission Replacement Pilot Program – NHTSA.gov

We hope you find the GM 9-Speed Automatic Transmission Fluid Level Check guide helpful. Check these troubleshooting and repair guides for more help on your GM.

Author

  • Rushit Hila • ASE Certified

    Rushit Hila, an ASE-certified engineer (G1 Automotive Maintenance and Repair), brings over two decades of hands-on experience in the automotive world to his writing. With a strong educational background, including a Master of Science in Engineering and a Bachelor of Science in Engineering, he has honed his skills and expertise through years of practical work. As a respected authority in the field, Mr. Hila is dedicated to offering insightful and valuable content that resonates with both vehicle owners and mechanics.

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