have a 2004 Blazer 4X4 been using the 4 wheele drive alot lately! Now I have this strange winding humming hollow sound coming from the left side of the vechile when not in 4 wheele drive! What could this possibly be?? Thank You

 

*Moved to a new thread of it's own* - The Helpful Threads post is for links to threads that have helped you, not for requesting help.

Have a read through this thread and see if it describes your situation:
4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO

Even if it doesn't go away when you put the transfer case into 4wd, it is still a problem with the front axle engagement.

 

possible wheel bearing ???