Bearing Race replacement
You are lucky, bearing races (or cups, as said in the other answer) on Shimano hubs are not replaceable but you can replace the rear drive side by replacing the entire freehub body. It can be unscrewed from the hub with a 10mm hex wrench.

I am not sure if the freehub bodies are available as spare parts, but it isn't too expensive to get a new FH-475 and use it for parts. You should replace the balls and probably the cone on drive side, too.

In my experience, the low end Shimano hubs (no name, Acera, Alivio) don't wear well. Even though XT has similar construction and doesn't cost much more, the sealing and materials are better and the result is far more durable. On the down side, replacing entire hub requires rebuilding the wheel, which will probably cost more than a new wheel if you don't do it yourself.