Noise in the steering column?

[FGHT ON]

I need some help here, perferably from someone who lives in the cold as well . . . I put 35x12.50x20 Mud Grapplers with 20x10 Rockstars on the '05 SUT about 2K miles ago (only have 19k on the truck). It was unusually warm here about a week ago and pretty cold again now. Now when I turn there is like a slight rubbing that seems to be coming from the steering column. I know GM is notorious for having rattling steering columns but this isn't that. It almost sounds and feels like maybe the power steering fluid is leaking and there is some dry rubbing but I checked that and not the case. A mechanic that I work with thinks it is just the ball bearings in the steering column acting up b/c of the weather change and that it isn't a big deal, not to worry about it. It doesn't drive or turn any different, but I have to take the truck into the shop next week anyway for some warranty issues and want them to take a look at it. Anyone had this problem or heard of anyone with this? Thanks.