My problem started soon after the drivetrain warranty ran out. Because of the problems I have had in the past with extended warranties as well as the cost, I chose not to put it on this vehicle. I plan to fix it myself, regardless of the problem. I am just looking for some information before I tear the front differential apart. I suspect it is a ring and pinion noise since it only does it when the front end is engaged and under power. When going down hill in 4WD there is no noise. This vehicle is completely stock and has never been used off road, or abused in any way.