Got a call from the wife that the car was making a loud noise and got worse when going faster. Told her to park it and I will check it out. I scheduled an appointment to go to the dealer and drove it there so that I can hear it as well. It was bad and described the problem to the service advisor.

After diagnosis, they said the rear differential went bad and needed to be replaced. Not sure if this contributed but this was preceded after one of the rear tires had to be replaced. This made the thread wear uneven which I think caused it to go bad. I also asked a parts guy that I know at Nissan about it and he also stated that you DO NOT drive long distance with the donut wheel as well for this same reason as it will take out the rear differential.

Since the car warranty was up just this past November, I was stuck with this $3,300 bill as the part along was $2300. I have owned this car from new and there was never any mention of needing to change oil in differential and would not have helped. Have to keep both wheels the same to avoid this problem and want to let you all know about this to avoid this costly repair.