2012 Subaru Impreza - Heavy front-end drivetrain noise

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Dec 17, 2011
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398
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Northern NJ
We're original owners on our 187k miles 2012 Impreza. Seemingly fairly suddenly, I'm getting a HEAVY drive-train noise out of the front. It's got at least a 1000 miles on it since the noise because bad with seemingly not particular ill effect except the deafening roar. Noise sounds exactly the same if I pop it into Neutral while at speed.

I've been through a a few of the notorious Subie wheel bearings already. It sounds kind of like horrendous wheels bearings. Hard to discern whether it is left, right or general.

On a previous set of tires, it had a surprisingly similar sound. This time, the sound is reasonably substantial, if reduced, even at low-ish speeds of about 20mph or even slower. Typically the bad wheel bearings for me require more speed to be noticed. Just put new tires on a bit early to rule that out completely, which it did.

I hand spun the front wheels while listening to back of front hubs with a stethoscope. I think I would hear something, which I did not, if the subsantial noise issue was due to a wheel bearing.

I'd think the front diff weeped fluid and ran too dry but I don't see it leaking a thing. I have been getting some axle clicking on turns. My best guess is bad axle. Any suggestions on how to diagnose further?
 

TCL

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Nov 13, 2020
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Don't the heat shields on those model years rust out? Just a thought, but maybe one of the heat shields is rusted out and somehow rubbing on a drive drain component.
 
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This is a guessing game but a couple of thoughts, boots do not have to be torn for a CV joint to be worn. Plunge inner joints like the ones used on Subaru causing a rumbling noise are common. What happens is the grease thins out over time and leaves the joint with most of the thin grease ending up in the boot, leaving the rollers dry and binding.
Clicking is sign of a failing outer joint. Cheap Chicom axles do not work especially well on these applications it is better to get a couple of low mile axles from LKQ and reboot them with OE boots and grease.

The wheel hub or other components cannot be eliminated without a thorough inspection.
 
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Virginia, USA
Don't the heat shields on those model years rust out? Just a thought, but maybe one of the heat shields is rusted out and somehow rubbing on a drive drain component.
Yes! I thought my wife’s CVT was about to grenade but luckily it was just a heat shield.
 
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Sep 17, 2012
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At that mileage re[place both axles.

axles.jpg
 
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Jan 20, 2013
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Ontario, Canada
This is a guessing game but a couple of thoughts, boots do not have to be torn for a CV joint to be worn. Plunge inner joints like the ones used on Subaru causing a rumbling noise are common. What happens is the grease thins out over time and leaves the joint with most of the thin grease ending up in the boot, leaving the rollers dry and binding.
Clicking is sign of a failing outer joint. Cheap Chicom axles do not work especially well on these applications it is better to get a couple of low mile axles from LKQ and reboot them with OE boots and grease.

The wheel hub or other components cannot be eliminated without a thorough inspection.
Thank you for this info Trav!
 

deanm11

Thread starter
Joined
Dec 17, 2011
Messages
398
Location
Northern NJ
Ordered two low mileage LKQ axles and will do as Trav said... Fresh axles, tires... that should clear it up and the clicking... will report back when I get to this eventually...
 

deanm11

Thread starter
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Dec 17, 2011
Messages
398
Location
Northern NJ
Follow-up : Got LKQ axles. Again, this sound was horrendous, way worse than previous wheel bearing failures I had experienced. I started with right axle. Zero change. Put in a Timken RF wheel bearing - silence. With the mileage, and clicking heard, it was time for axles anyway. The bad hub/bearing off the car makes a bit of noise but is surprisingly smooth... might not think anything without a new one to compare to. Wow.
 
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