It's a 2002 Suburban, I just bought this spring. I tried the 4wd last week on the snow and ice, and it worked great....however there was a whirring noise that developed from the front driver side and I am curious if there is a periodic maintenance/ lubrication point that needs attention.

Never owned a 4wd vehicle before this one. As mentioned, no problem selecting 2wd, AWD, 4lo or 4hi. But anytime the 4wd engages the front end gets noisy. Any suggestions?

 

you should change the front diff fluid. not sure on the noise.