04 rancher at.. shifting problems.

Hey everyone. I am new to this so please bear with me.
As I stated above. I have a 04 rancher 400 AT and the problem I am having is when riding it will not shift out of first year when in auto. And when its in reverse it feels like it has four flat tires and stalls out. When I to switch to ESP mode its doesn’t do anything. I am trying to figure out where to start.. Any help would be greatly appreciated.