Automatic box Jeep Grand Cherokee Laredo 97

Hello friends, I hope I can help me with this problem I have a Jeep Grand Cherokee Laredo 97 and from a moment to the changes were crazy in neutral and in reverse the truck walks forward only is only turned on in a parquin that could be and how it can solve I have another doubt I respect how it should be used or how the double traction Even while the four wheels work forward and when I put it backwards, a taberite that says it and work the four wheels, please you can collaborate explaining that I must do with respect thanks thanks