I have just returned from the Nissan dealer - it seems that the front differencial is suddenly leaking 75W 90 gear oil from the plastic housing for the 4 wheel drive actuator unit. It is under warranty - truck has only 14000 miles. It is the first real problem I have had in over 2 years. Has anyone else had this issue - and how big a deal is this? Will the front differential fail down the road because the fluid leaked out? What has been your experience?