Also for the mechanic to say the failure happens "typically" at 20K+ miles, Its a mighty small sample size with most Gen 3s being under 20K miles. I had an Xterra a while ago that had a near 100% failure rate of the transmission fluid mixing with the coolant causing immediate transmission failure usually at 75-120K miles caused by a poorly designed radiator. They fixed the radiator design eventually, but on rare 1 off occurrences it would still happen. Just because something is fixed doesn't mean a mechanical part can't fail. If the gen 3 phasers still had a issue like the gen 2s had we'd be seeing threads crop up on them almost daily.