C56 gearbox

[Roycep27]

Hi there need some help just rebuilt my c56 box new bearing and fitted a kaaz 1.5 way diff. But I have a problem I have rebuilt the box and jacked front of car up and drive it 1 2 3 4 5 as normal but put it in reverse and try take it bak In to nutral it won't come out reverse only way can take it out reverse it put it in to second then it will come out. I took box bak out and stripped it again but can't see the problem. Only thing I can think is am not putting the gear selecter part where the cable attach to am not sitting in it right any help ?