I need help . We went to go on a 240 mile trip up the MISSISSIPPI river yesterday and my lower unit went out on my alpha one. I limped it back to the boat ramp got it home and my neighbor had a good pre alpha one lower unit. I put it on, I can't get it adjusted so It shifts into both gears I have a clymers but cant figure out why I'm only getting one gear am I missing something here?????????????? please help so we can take our trip.