Why is there a grinding noise when I am in 4WD

What is your question?

I noticed a grinding noise when in 4WD Low and high when I start driving about 15 mph. I’ve tried to research the problem and I’ve seen stuff about a front differential or a pinion. There is no noise or grinding when in 2WD, it did start snowing today and getting into freezing temps but I’ve never had a problem with this until now. I have a Chevy Colorado 2007 thank you for your help.

What makes this problem better or worse?

N/A

How long has your 2007 Chevrolet Colorado had this problem?

Few hours