4wd noise

Hello,
Got a '93 s-10 Blazer 4.3. When driving in 2wd after about ten miles at 60 mph I get this deep hum out of the front axle. It grows in volume as I slow down until I get to about 5 mph. Then a clunk and it's gone. If I shift it to 4wd without slowing down it makes it go away completly too. I'm thinking something in the front differential possibly transfer case? Mind you some days it won't do this at all. Some days many times a day. Seems to have nothing to do with weather or conditions.

Thanks,
-Mark

Start witt checking the fluid levels?
Does noise change on pull or coast or turning the wsteering wheel left or right going stady down the road?

Here is a link for rear end noises.
http://www.differentials.com/install.html

Also try removing front drive shaft and see if noise changes.

Turning makes no differance in noise, i think. I live 20 miles from town on a highway. Straight road. i have had a gradual turn there. Coasting makes it a bit louder but it gets louder gradually it's not immediate maybe a second or two. If i give it hard gas it almost goes away but is still present. Will check fluids tomorrow if it's not too cold. I live off Lake Superior and it snows and the wind blow 24 hours a day this time a year.

Thanks,
will post findings.

-Mark

You are welcome and let us know what you find.
When checking fluid levels have a good look over under there.

Well I haven't crawled under it as we are on our 26th day in a row of measurable snow. Anyways I had a thought. On my dash the 4hi light has never lit since I bought it in August. I was assuming it was a bad bulb. The 4lo does the flashing where to get it into gear I have to do the park neutral park thing. I'm seeing more and more that that an out bulb on other GM vehicles may be telling me something however the 4wd does work fine other then the noise when its off.

-Mark