I would say this is not normal but then again I've never removed an axle from an America. I would try to get a little oil such as WD-40 into the spacer to try and free it up. Soak (Spray) it pretty good, tap on the spacer VERY lightly to help free it up after you have some oil between the spacer and axle. It might take a good while to free up the spacer, just take it slow and easy.
When you go back with the axle be sure and grease it.
Like I said, I've never removed an America axle so proceed with caution if you try my above comments.