Good Grief...
 

Here we go again! Hi folks, I have a humming/rubbing kinda sound coming from the front axle, again... I replaced the front passenger wheel hub 2 months or so ago and the noise went away. It is back again though. Unlike before, the noise seems to be coming from the middle of the front axle, not like before when it was definately the passenger side... I don't think it is the driver side wheel hub, no play after jacking it up and trying to move the tire top to bottom or side to side... I have a 98 Blazer LT 4 door 4x4... The sound is there 4hi, 4lo and 2hi if that narrows down the possible advice anyone might have... Strange to me though, 4 wheel drive is working perfectly... Thanks for any help you all might have on this problem...

As we know, vibrations can travel strange and unexpected paths to us. Until you said you inspected the other hub directly by check for free-play I was going to suggest it as once one goes out, the other cannot be too far behind.

So the sound is definitely synced to the speed that the wheels are spinning?

I wonder if a hub could transmit a sound like you are hearing as it is going bad but not so bad as to have there be much free-play in it.

The sound is there no matter the speed, the slower I go the louder it seems. The faster I go the less sound I hear, but it is still there... Maybe the same sound but higher the speed the less likely I hear it due to road noise? I am at a loss, like I said, 4x4 works just fine, 3 button switch by the way... Can an axle just "wear out"? Maybe I need a new front axle??? Dosen't make sense at this point... Too be as accurate as I can be, it is more of a "humming kinda sound" rather than a "rubbing kinda sound"...

The front is cv, if they were to go bad, you would probably hear a clicking sound while turning. There is an "axle" coming out of the front diff, with bearings, but in 2wd the passenger side won't be spinning, since it's disconnected.

I've had a rear axle actually "wear out, " the bearing wore a groove into the shaft, and I had to replace the shaft. No noises whatsoever, just a gear oil leak that I couldn't stop by changing the seal and bearing

Hi there Mr Red... No sir, no sound turning the wheel all the way to the left or right, no "popping sound"... I am starting to think maybe my front transfer case, switch, motor whatever might be the cause??? Still seems weird though, 4x4 still works great with no problems... I even rotated my tires, even though I did that a few weeks ago hoping that was the sound, but no, still there... Also, thanks Christene... Dangest thing though, everything is working just as it should, just that "humming" sound. Nothing is acting funny, no pull to the left or right, let the wheel go and she stays straight as an arrow...

Just turn the radio up a little louder. When the noise get really bad, it'll make troubleshooting easier lol
​​​
As the noise stays the same in 2wd and 4wd, I wouldn't think anything with the tcase, etc, would be it, but who knows.

Maybe some kind of bearing in the front diff? The spiders and driver side axle are always spinning, 4wd or not

My guess - hub bearing dried out and singing but not wore out far enough yet to have slop ....

Always a possibility also.

Might be the driver side wheel hub... I think I will go ahead and replace it since I replaced the passenger side a few months ago... Wasn't very expensive and it won't hurt to have a new 1 I guess lol! I will report back after I do it sometime this weekend...

I went ahead and replaced the front driver side wheel hub the other day... I am very confused now lol... The noise is only there in 2hi, not like before when it was 4hi 4lo and 2hi... How is that possible??? I am at a loss here gang, any more ideas? I would hate to put it back in the shop only to find out it was something simple I missed...