Remove the drive from the bell housing (bell housing is what the drive bolts to, then the bell housing bolts to the gimbal housing).
Remove the cable from the shift bracket (inside) and unscrew the ends off of it.
Unscrew the cable from the bell housing (outside), they have a special tool for it but you can get it done if you work at it.
Loosen the cable bellows from the gimbal housing (outside underneath the bell housing).
Tape a wire to the end of the cable inside the boat, you can pull the inside of the cable out if you need too. (You can put the new cable in without the insides of it too and slide them in when your done from the outside).
There's a gromet on the inside, it may or may not hold you up, you may have to push it out from the outside pushing in.
Pull the cable out, untape it and tape the new cable to it, pull it back in and reverse the steps.
It's easier to pull on the wire while someone is pushing on the other end.
I probably forgot something but you can call our shop if you get in a jam and I can walk you through it.