Step # 1 is to remove the lower unit.-----Then with the lower unit in nuetral you measure from the mating surface to the center of the hole in the shift rod.---Write down that measurement and post it here,
Model # is ??--------The lower unit itself DOES NOT care what gear it is in.------You may need to shift this thing to disconnect the shift rod.
You should be able to find nuetral with the lower unit off !----------Shift it a few times to get the feel for nuetral.!