I had a flat tire on my 2017 sport (4 wheel drive). Donut tire was put on. As i was driving to tire shop, the drive train warning lite came on. The mechanic at the shop told me the reason for this, was because the fluid was getting hot. The smaller donut tire was the problem. Never heard of this. Why would nissan put a donut tire spare on four wheel drive cars? Thinking about getting a full size spare. Anyone have this problem? Sorry for the long post.