please help!

[misfits]

I've got an 86' GMC that ive been working on, on and off for a few months. I swapped engines in it last week end.
now i finally got it all put back together and i broke the bendix on the starter. I swapped some parts from another starter and all it will do it click. Tried charging the battery and tried jumping it.
Tested the starter on the bench and the motor works well and it will kick the gear out too.
I've got the wire on the starter from the coil but i dont remember if there was a wire on the opposit small post or not. Or if the problem is in the bendix itself from when i broke it.
I ended up swappingthe plastic cap on the bendix cause thats what i broke.
I dont know if any of that makes any sense or not. maybe somone can point me in the right direction. I've been working on it for so long now off and on that i dont remember anymore lol.
thanks!