Hi group. I own a 2017 6.2 Gas F350 4x4, 175000mi. I seem to have a very faint "whirring" noise. Not quite tire drone, and it seems to be coming from XMSN/T-Case area. The noise seemed to show up after some extended 4x4 engagement, during a blizzard, on an interstate. Yes, I know it is not recommended, but it was the situation I was in. The noise is when in both 2WD, or 4WD. Truck is preforming normally, and no diagnostic/trouble codes. The XMSN fluid only has around 15000mi on it. Thoughts on cause and/or remedies?