I have a 1997, 3500 dually 4X4 with the 12 valve and the 47re tranny, does anyone know of a way to put the 3rd to fourth gear shift, or rather Over Drive activation om a switch to bring it in manually? I have the T.C. lockup switch installed but would also like to put the O.D. on a switch as well! Any help would be greatly appreciated!! Tommy