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Symptoms of 5MT stub axle or differential carrier bearing failure?

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1999 Forester

200,xxx miles

Original trans


This all started with, what I thought, was a bad wheel bearing.  "wub wub wub" noise on left turns indicating the front right bearing, shimmy while breaking at highway speeds (brakes and rotors all around done about 2 months ago) 


When I first noticed the noise, I jacked the car up and spun both front wheels as well as rocking them at 6 & 9 but I got no noise or movement.  Couldn't hear anything from either knuckle with a long screwdriver to the ear.  So I decided to wait a bit for it to get worse so I could identify it.


The sound is so bad now that I hear it driving straight, left and right, but turning to the left remains the loudest.  Last weekend I jacked the car up and took another look.  Still no movement in either wheel, no indication that the seals have gone bad, but I did spot a torn boot on the DOJ on the driver's side.  I grabbed the axle shaft and it had a lot of play.  I compared to the passenger's side which also had some play, but the driver's side had substantially more play.  


At this point I figured since I didn't have any other new info, and that axle would need to be changed regardless of the wheel bearing issue, I decided to change it.  I pulled the axle and while I had it off I rocked the stub axle and it has some wiggle.  I don't know if these should have any wiggle in them, seems to me that if they are under preload that they really shouldn't.  I didn't pull the passenger's side axle, but it has some play at the DOJ too.


I put everything back together with a new axle and tested the play in the axle shaft again and it seemed to match up with the play in the passenger's side.  I went for a test drive and the noise is unchanged.   I'm worried that I have some bad bearings in my trans. 


So my questions are, when the diff carrier bearings go bad, is there play on both sides? 

If so, then are they both bad? 

If not, then how do I determine which one is bad? 

and lastly, and I'm not holding my breath here, are these bearings I can get to without tearing the trans apart?


I have not yet changed the trans fluid to look for metal shavings as I ran out of light/energy, but that's first on the list tomorrow.


Thoughts opinions?






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Hey Will! Glad to see you're still around!


The stubs are not press fit nor are they a tight fit. They have some room between the diff carrier and stub to allow an oil film for lubrication. They wiggle a bit but it doesn't hurt them any, nor will it cause a noise.


Carrier bearings hardly ever to bad unless something strange got in there and that's kind of a stretch.


Wheel bearings on these are common failures as im sure you know, but often have very little or no detectable play until they're completely shot.


I just replaced the left front wheel bearing on my Legacy which has been making noise for about two or three years, as far as I can remember. The "turn test" said it should be the right side. When I turned right the noise would subside, and when I turned left it would get louder. Upon disassembly of the bearing I found the inner race (toward the trans) of the bearing was worn and the rollers were pitted. The outer (toward the wheel) was fine. This even stumped a couple of the instructors at school who swore up and down that the right side was bad. I made sure with the chassis ear kit before replacing it. I couldn't afford to do it twice. Left side replaced, and my whirling grumbling noise is gone.


The best test I can offer (in lieu of a chassis ear kit) is to remove the axles so you can spin the hubs with no resistance. Once the axle was out on my car the bearing damage was easily felt and heard by quickly spinning the hub.


Also, don't rule out rear wheel bearings. They seem to fail more often on the Foresters for some reason.

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Thanks Fairtax, good to see you around too.  How's the weather out there?  We were back in Catlett in January for my G-pa's 86th and man do I miss the Va country.  We did a nice hike up Old Rag, found a late 1800's graveyard.


Good to hear that there's some wiggle on the stubs.  I really couldn't remember if that was supposed the be the case or not.  I'm actually not that experienced in wheel bearing failures as I've never had any in any of the subs I've owned. 


Well, I guess I'll tear into the right front hub and see what I get.  I'm pretty confident of the left being good since I was just in there and didn't see anything amiss.


I suppose to be thorough I should jack up the rear, but the noise and grinding vibration/sensation really seems to be coming from the front.



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