904 pushbutton with no neutral

I think adjusting the cable is the key. Or at least an easy first step. I have a couple manuals neither describes the adjusting to any depth. The good news is I did find neutral. It was hiding between it and reverse. I feel like I'm looking for that perfect note on a tuba!

See if this helps.
http://www.1962to1965mopar.ornocar.com/transtech.html

Everything I see says the best way to adjust it is with the pan off.