2001 Dodge Durango Will not engage

I have a 2001 Dodge Durango V8/5.9L with AT. A couple of weeks ago my wife was driving and the trans heat light came on. It was hard to shift but she made it home. I did a transmission fluid and filter change, transfer case change and oil change and then reset everything by disconnecting the battery. If you put it in 2nd or Drive it will not go. However, if you put it in 1st it will go and at a higher speed you can change to 2nd it will then engage and then at a higher speed it will engage in Drive. I read that when the trans heat light comes on their is a sensor that shuts down shifting to keep you from burning it up. Is this true and how do I reset this or should I be looking to change a sensor? Thanks!