Transmission does work in forward gears?

It sounds like the forward clutch pack is bad. When's the last time you serviced the transmission? The transmission should be serviced every third oil change.

We should run the codes because it sounds like the first gear shift solenoid is not working, this guide can help, and I have included how to change the shift solenoid out in case a code is present for it.

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

This guide may help as well:

https://www.2carpros.com/articles/automatic-transmission-problems

Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.