It wants to grind going between 2nd and 3rd gear

It does sound like a fluid or pump issue so we need to start with a service. Here is a guide that will help with this: This video shows the job being done on a similar car but the process is the same.

https://youtu.be/NUOBl4bqtss

and here is a guide to help you step by step with instructions in the diagrams below to show you how on your car.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Below is the process from the manual that will help with this as well. Please let us know if you have other questions. Thanks