4x4 quit working

I was driving to work the other day and my 4 wheel drive quit working. I live in Ft. Wainwright AK so it stays in 4x4 for 5-6 months. Any way when I try to reengage it I hear clicking the light comes on and still no 4 wheel. The tempatures up here are low last week -40 thru -50. Any advice as to where I should start and steps to take. I have limited mechanic skills. Is this something that I should just take into the shop?

you hear clicking you said hmmmm is it posible you had your wheels rotated or removed recenty?

you hear clicking you said hmmmm is it posible you had your wheels rotated or removed recenty?
Not recently, it started working the other day, but it still does not seem right. It is making a grinding sound when I drive.