First check your lower oil for water and broken parts. Next take the cable off and manually shift it to see if the lower is working. Then run the control box to see if the cable is broken. If the cable is OK and the box shifts, Your out of adjustment. Remove the 2 side covers to the lower section and you will find a turn buckle type connector. Adjust it in and out till you find neutral. Next adjust the cable so it pops on the motor when the control box is in neutral. If any of the above are broken, you will need parts.