Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

Front end noise - humming

23K views 14 replies 8 participants last post by  chevychick04 
#1 ·
Hi Everyone,

I've been coming to this site for a while to get some answers and have really appreciated the knowledge base here. I've searched and haven't been able to find an answer to the problem I'm having.

I have an '04 TB with 127,000 miles on it. I recently starting hearing a loud hum coming from the front end. It got louder the faster I went. My first thought was that it had to be a wheel bearing. Driving straight and turning right, the noise was there. It got quiet when I was on a curve to the left. So... I changed the right front wheel bearing. I pulled it out of the garage and drove it down the road. The noise was still there. I pulled it back in, removed the bearing and re-installed it thinking I might have not torqued everything properly. All back together and down the road again.... the noise is still there :cry:

I talked with a guy at the parts store about the bearing. He said it is EXTREMELY rare to get a bad one out of the box and suggested I check the front differential. Sure enough, it was low on fluid, so I drained and refilled it (not sure the last time it was done).

Once again, out of the garage and down the road. The hum is still there. I'm at wits end. Can anyone tell me what the problem might be?
 
See less See more
#3 ·
I too think you changed the wrong side.

Think of it this way. Where is the heavier load when you turn the wheel right? On the opposite side, i.e. the left. When you turn the wheel left, it lifts some of the pressure off the LF bearing.

Then think of this. When is a bearing likely to make noise? When it has a load on it, or when it doesn't?

So, IMHO, you changed the wrong bearing.

But don't despair. Look on the positive side. You discovered that your front diff was low, avoiding a potentially expensive repair, and you will now have two new bearings. Sometimes it doesn't get much better than that. :)

Just my :m2: as well.
 
#5 ·
That's true. You "can" use the 127,000 mile bearing. And it may last a while. But given how much labor is involved in changing it, you might want to simply be done with the job for, hopefully, another 127,000 miles.

But yes, you "can" just put the "'good one" back on the other side.
 
#6 ·
I appreciate the help. The bearing is a 1 piece, sealed unit, so no re-using it on the other side. Not sure I'd want to with the miles on the truck any way. I guess it looks like I'll have to bite the bullet and replace the left side now.

Gotta look at the bright side I guess. New bearings on both sides and I saved some major damage to the front diffy.
 
#8 ·
This does have me wondering though... was the right side bad to begin with? Or has it been the left all along? It's a pretty quick change out (less than an hour) and I have more time than money right now. If I threw the old on on the left temporarily I'd at least know. Or is that a bad idea?
 
#14 ·
Finnally Back and Envoy has an issue

Wow been a while since I'vew been on the thread, been over seas, but with that said I came back and my couisins Envoy is doing the same thing, it was fine two weeks ago but started after we had the car shipped to Washington from Florida. I am gonna check the bearing but need to look at what side... gonna searh the threads to find a exploited diagram to make it a bit more helpful when I take it off. Any recommendations before I start???
 
#15 · (Edited)
I'm having the same issue. I wouldn't say mines a humming noise... almost like a ticking noise... like if the tire is rubbing on plastic... but I checked to see if it was hitting anything and it doesn't seem to be... it was only when I was turning right... but today I had my window down and it did it when I was turning left... I'm gunna have to take mine somewhere tomorrow to have it checked out and hopefully not pay an arm and a leg!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top