I have had this suburban for a couple years now, and the 4 wheel drive has always worked.
Just before that past christmas we had a huge snowstorm and everything worked fine, but then 1 day I waited for it to cut on and it just didnt.
I dont know if this matters or not but I recently put bigger tires on it than normal and 1 time whilr turning I heard a loud nosie sounding like it came from around the driver side front wheel, but the 4 wheel was still working..
Any suggestions