FYI: Front humming noise diagnosed and fixed

[MSP2003.5_Nick]

2004 mazda 3 GT Sport 2.3L

Hey guys, just wanted to post some information about a problem I had that I could find no information on. So if anyone else is having this issue here is what I went though.

So I noticed a humming noise coming from the front. Got louder with speed and made no change turning left or right. I switched over to my summer tires to see if it was road noise and checked wheel bearings for play. This was not the issue.

I looked around under the car and noticed a fair amount of play coming from the half shaft. It would move in and out of the transmission about half an inch and had a fair amount of side to side play. So I thought easy It's just the carrier bearing gone bad.

Took the halfshaft apart and got the bearing number, it's a 6206. Got one at a local parts store and replaced it. Then I found the real issue. Upon pressing in the new bearing it still had the half inch of play in and out. The outer race of the bearing wasn't gripping the support bracket at all. This is a new bearing so it definetly didn't shrink.

I looked around further and found a TSB for the ford focus with the same motor and trans. There was a recognized issue with the bearing support bracket wearing down and having the bearing sit loose on some vehicles. They had since redesigned the bracket to fix the issue.

I didn't want to spend the 400 on a new dealer half shaft so i opted for a junkyard replacement for 80 which completely fixed my issue for now, and hopefully forever. It was off an 08 so hopefully it has the redesigned support bracket.

So in conclusion if you have this problem don't waste your time replacing the bearing, just get a new shaft.


I just wanted to put this info on here cause everywhere I looked I was told it was wheel bearings and tires and a million other things which didn't help at all. Hopefully this will help someone.

 

[Cliff]

I just got new tires after reading how a bearing noise will increase on turns, and my car didn't seem to do that. The tire guys said the noise was "in the gearbox" and I needed a new or rebuilt transmission. I also have a 2004 and probably would have gone crazy going to mechanics and getting false diagnoses. Thanks so much for posting this!

So did you examine your old carrier bearing and did it seem good. I want to take your advice and just replace the shaft but I'm wondering if the lack of support may have damaged the carrier bearing and am thinking I may as well replace it once the work is being done. Any opinion?

 

[3style]

I just replaced my wheel bearing today and still have the noise and feel ( feels like a bent rim ) which gets louder and more pronounced at higher speeds. I hope this is the also the cause of my problem. Is the shaft easy to replace.