How much whine is normal for a new sure grip rear end?

When you put them (proper lube in diff housing) down you should slowly/'grandma-like' drive them, slide-to-slide turns for a little bit and they should be quiet. No whine.

And at low speed if you had a wobble in your driveshaft, it would be pretty epic- how you would not visibly see it with your naked eye would be a mystery to me