Overdrive light flashing and transmission is not shifting properly

Hello, I'm Danny.

Yes, it definitely sounds like you have a transmission trouble code stored in your cars computer.If you don't have access to a scanner or code reader most local auto parts stores like AutoZone will check for free. Here is a tutorial showing what is involved:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

After the scan is performed get back to us with the code numbers and we can then properly diagnose the issues.Hope this helps and thanks for using 2CarPros.