97 Blazer 4WD fulltime has extremely loud grinding noise
 

Front passenger side or center right noise, Noise started in summer , replaced brakes and wheel bearing
{complete hub}
For a while I could make it go away by backing up a few feet then going forward again The noise sounds like metal on metal ? appreciate any help I can get. Thanks {problem has become more frequent as time goes by} does not always do it though

Your title is a bit misleading.. Do you have the push button 4wd system or the fulltime AWD system in your truck? Both were offered in '97.

It has pushbutton ,sorry

OK.

Sounds like your front axle engagement collar is not disengaging properly when you select 2HI. Search for "collar" and you should find a picture or two and some pertinent discussions.

you broke it...now go fix it...lol...thats about as much help as i can give you lol

Thanks for the help guys , turned out the cable for the 4 wd was not operating because it was rusted , sprayed some penetrating oil on it and works fine now

Glad it was something simple. When the weather gets better, you may want to consider removing the cable and really getting it lubricated throughout the whole cable to try to stave off future problems.