Well my experiences with Nissan dealership's service departments has always been very good, some of their techs were not hitting home runs, but they tried, and eventually succeeded.BKW said:
But as Nissan vehicle buyers, we are paying for a 60,000 mile power train warranty. It is not out of the goodness of their hearts that they repair the seals, but out of a contractual obligation. If they didn't do this, many would simply take them to court.
As far as mods, the federal government's Magnuson-Moss Warranty Act clearly states the car manufacturer must prove that the mod caused the issue - an expensive proposition for them to prove this. And what jury would side with the manufacturer anyway. People have been mod'n for decades.
And if Nissan were idiots like apparently [edit: according to you anyway], the big three are, people not wanting to deal with court, would simply wait until the axle drained dry and it would cost Nissan 4x the price of a seal replacement to provide a new axle. It's called a power train warranty and that is what it is.