I have a 02 blazer ls 4x4, at first I was getting a thumping noise that would happen maybe 3 times then stop. I could hear some squealing randomly while driving, it's never constant either. I talked to a buddy of mine and he was thinking wheel bearing so I changed out both front bearings. That wasn't it. Took it to belle tire and they told me tires are bad, had stepping and flat spots. So now I have new tires on and still does it. I also took it to a transmission shop and they said there was a little noise coming from the transfer case but it's 140 for them to pull it and check it inside. Do you think that's worth it since they can't tell me it's the for sure cause?

 

Have you checked the condition of your parking brakes ? I have a 4x4 4wheel disc and I had a scraping squealing problem that was caused by worn out shoes. When I bought the Blazer the inspection was less than 30 days old !