I apologize in advance if this has been covered in the past, but my search resulted in nothing...

I have a 2000 2dr 4wd ZR2 with 87,700mi on it. I was coming back from the airport this weekend and I started hearing a sound that reminded me of a remote control airplane coming from the right front tire. I had a buddy ride with me and he said that he can feel a vibration in the floorboard on that side, but it's not severe enough for me to feel it from the driver's side. The sound is much much louder at lower speeds, and as far as I can tell, turning makes little or no difference in the sound. It still handles like it always did. Anybody got any idea what could be going on?

 

maybe a tire problem, feel around on the tire and see if there are might be a broken belt or if the tire is wearing irregularly

 

Is it like a faint clicking? It is possible that it is caused by a partially engaged front axle.

What happens to the noise if you put it into 4wd?

 

The tires have a lot of life left on them, but the 4wd is a possibility, I'll give it a shot.

Ok, the 4wd seems to be the problem. I engaged the 4-hi and the sound stops. I stopped, put it into 4-lo, and still no sound, when I dropped it back into 2wd the sound went away. Any idea on how to keep this from happening again? Is it something I need to get checked out?

Thanks for the info!

*edit*

See also:
https://blazerforum.com/forum/2nd-generation-s-series-1995-2005-tech-41/4wd-engages-itself-9585/