I have a Chrysler PT Cruiser, and when going down freeway it does not die, but it won't go into gear. It was running fine and then it will just stop. It is still running and doesn't slip. I also just had a new radar put in and the car will start but it wont go into a gear.
I would start by checking the transmission fluid, axles and shifter cable. If the fluid is low, or shifter cable is out of adjustmen, these two things can all prevent the transmission from engaging and applying power to the wheels. However, if all of these things check out ok, chances are the transmission is bad and will need to be replaced or rebuilt.