Try putting the gear in reverse. Then look from the left side to the selector under of the car. On the bottom of the cover it has an opening inside which you see the end of the gear stick (if in reverse). There is a small hole across the end of the gearstick. This hole should be in the center of the opening. Usuing a suitable tool is can also be locked to this position. Then one can slacken and reticken the selector arm and it should be spot on.