Back up lights on forward and reverse

.............This problem occurs when the linkage inside the trans is the old style[68 down] combined with a 3 prong nss from a 69 up car/wiring harness...........68 down uses a single prong nss..........and yes u can change the linkage inside commonly known as the rooster comb.....68 down is bare metal.......69 up has a plastic comb.........kim............