noise goes away when I press the button to engage the 4wd

2000 CHEVROLET BLAZER
118,000 MILES • 6 CYL • 4WD • AUTOMATIC
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BENPRIOR
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  • 1 POST
My Blazer makes a loud humming noise when I travel at high speeds or go up a big hill. The noise is coming from the right front wheel. The noise goes away when I press the button to engage the 4wd. The noise also can barely be heard when going fast and increases in volume when I slow down. This noise use to happen once evry couple years but now seems to do it anytime I am traveling fast. I would apperciate any help.
Jun 16, 2009 at 4:44 PM
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SWILLIAMS
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  • 597 POSTS
Take it for a drive and switch it in/out of 4X4 a few dozen times. That might free up the sticky vacuum switch to the front axle. What your likely hearing is the collar on the axle interlock almost engaging and grinding. If that doesn't free it up you can spray a bit of silicon into the vacuum lines and let it set a while to soak into the various valves. Then cycle it some more and see what you have.
Jun 17, 2009 at 12:54 PM