My 2012 Leaf has about 35,000 miles on it. Twice when I have had it in for maintenance, at 15,000 and 30,000 miles, the dealer has told me the reduction gear oil was bad and needed to be replaced. I have searched for this online and have not found that anyone else has had this issue. Is this a known problem? Is it even remotely possible that they are telling me the truth? Or am I being fleeced?