Ok guys, I have a 1987 Cherokee 4.0 4x4 automatic ..My problum is my tansmission wont shift on its own..Theres a connector under the hood that is unhooked and it allows me to manually shift and it works completly fine that way..It goes smooth through all the gears..Does any one kno what causes this..I no its electrical cuz it shifts fine manually but i also no its not a long term fix..What would cause this..Thanks

 

Any ideas?plz any help would be greatly appreciated