Sounds like a wheel bearing. More noise on left turn almost confirms it.

Don't be fooled, there isn't always 'Play' at the tire with a bad bearing on these Sealed bearing/ hub setups.

 

Ok...long time no update, but here we go:

The problem got worse recently, seeming that the Blazer couldn't go further than a mile before it started to make the rumbling/bad bearing noise from the front end. The left turn thing doesn't apply anymore. It will kick in during right turns too, now.

Someone suggested that I change the transfer case switch (the one with the 3-hose connector); I did so tonight, and while it seemed to help somewhat, it didn't completely solve the problem. Still makes noise intermittently, and once it starts, the noise will not go away until 4WD is engaged.

I heard a little bit of clicking coming from the front end on the way home from work today, too....new symptom in all of this. I am totally stumped. I haven't tried checking the actuator cable at the front diff yet....the skid plate/brush guard mounting bolts are seized.

 

4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO

See if that helps.

 

Not sure if this was discussed but have you disconnected the Cable that runs from the actuator to the front axle? Disconnect it at the axle. Maybe it is rusted and never fully disengages.

 

Hi guys, thanks for the replies. I've read that thread before (thanks , though, Swartlkk). Aside from disassembly everything to visually inspect bearings, the cable is the only thing that I have not been able to check. The bolts holding the skid plate in are seized, and I can't get to the front axle. At this point, I think I'm just going to have to drill out the bolts or grind them off.

On another note, I had a question about removing the front axles. I was thinking along the lines of removing the axles to see if the noise goes away or not (ruling out the front axle vs wheel bearings), but threads I've seen all seem to say that you have to leave the outer CV joints torqued in the hubs. Why is that? Will the bearings fall out of the hub without something torquing the mess together?

 

most certain its the wheel bearing just change them. prolly been on there since they were put on at the factory. there like 43 bucks on ebay and like 75 for a pair with the abs sensor. if that dont work at least there new and not have to worry about them for a long time. then change the cv axle or regrease and put a new boot on to see of the noise goes away.

 

100% YES the Hub can and will have a catastrophic failure id the shaft is not in place!!!!!!!!!!!!!

 

I'm trying to envision that .. dont worry, though, no one will be injured unless they are standing too close when you put the truck on the ground. But you'll need another hub.

I know you're operating from theory right now. You see when you start getting into the fix.