I finally was able to get the car examined and they told me that it’s the “pressure control solenoid”. They say there’s a TSB on it, so it’s happened to other people.
The solenoid itself is $58.19 and labor to install was quoted at $414.09. They also recommended a fluid and filter change. Total price would be $691.99 after tax.
Just wanted to post an update in case anyone else comes across this. I’d like to thank everyone that posted for their help.