I've been through this with slapsticks myself. Loosen the small bolt that clamps the small metal "box" on the arm that attaches then to the trans lever. Push the trans manually (while under the car) into 1st. Put your slap stick in first, then tighten the bolt on the "box". Make sure that you are in the middle of the gear you selected. Next, test in "Park" to see if it is engaged there. Try running through the gears with out running. If not working quite right, try the above procedure in "Drive"