help alpha one outdrive merc 5.7 no reverse

[ridemewrongway]

i disconected the shift cable from the top of motor and then turned the gimble and got nuetral and forward just fine but reverse will not go into gear if i apply pressure to it i turn the prop and i can feel the reverse but its not going all the way into reverse gear what could be the problem? the shift cable slides easy and moves pretty free so i dont think its a cable... anyhelp would be appriciated