Transmission ( shifting gear problem)

Any time we have a transmission issue we need to start with the fluid level and condition. This will give us insight into what the issues could be.

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

I assume you checked the fluid but let us know what the level and condition is and then we need to do a stall test.

I am attaching the info below on this but please run through this and let me know what you find with this.

If the fluid and stall test pass but you still have no movement then more than likely the pump has failed and at that point, I would just rebuild the unit because you are going to have to go into it and replace the pump.

More than likely you will find metal in the unit which means it needs to be rebuilt as well.