2003 dodge 2500 4x4. 84k miles, 35" tires. Long Box

there is a high pitched sound coming from my truck. itisn't a whine or a squeal but is high pitched, kind of like a quiet turbo sound.

it seems to be present more when it is cold (in boise ID) it also seems to change with the transmission downshifting (like coming to a stop light)

it doesn't seem like a dry bearing (wheels or axles)

it does sound kind of like a "gear whine" but quiet.

any ideas about what this is?? is my tranny going out? (auto) my TCC? Tcase? Carriage Bearing?? help....

Thanks

 

I have same issue. (or I think its the same as yours)
2004 3500 4x4 115k 35s short box

I found it goes away when I engage the "tow/haul"
Since I think the T/H locks the torgue converter I am thinking the TC is on its way out.

 

Sorry I cant help (I am stupid about drive train stuff). Since it seems worse when its cold perhaps you need to change your fluids although after driving for awhile they should be heated up enough to not be an issue. Hopefully somebody else will have some idea's for you.