Renegademechanic

I just installed an input shaft bearing on a getrag nm290. Everything went great, that is until I tried to tighten up the bearing retainer. When I tightened it up. The shaft got stuck as if it was pressing against the output shaft, and when I turned it with vice grips, they both turned even though it was in neutral. When I loosened the retainer, I could turn it by hand and I could hold the output shaft when I turned the input shaft. I'm missing something, but not sure what. Help??? Thanks.