Subaru Outback Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
My 2009 Outback manual has started a speed related whine, that increases in pitch as speed increases, and independent of whether clutch is in or not.
From reading messages on forums seems it may be a wheel bearing (93000 miles all originals). I'm going on holiday for about 500 miles next week so if it is a wheel bearing I'll leave it until I get back. The one thing I want to be sure of though, is that it isn't the AWD system - I had new tyres fitted about 6 months ago on one axle, the other 2 are about 50% worn - so maybe 1/2" difference on circumference. Would the AWD system cause a whine?
 

·
Registered
Lawn ornament XT
Joined
·
14,368 Posts
It sure could- mismatched tires on opposite ends of a Subaru is a well-known formula for maximum stress and wear on the AWD & transmission.

All of the (multiple) bad wheel bearings I've heard in my 2006 didn't have much of a whine. They had a full-spectrum roar like an aircraft engine.
 

·
Registered
2005 3.0R
Joined
·
227 Posts
I have a front wheel bearing/hub assembly that's on the way out... The sounds it makes run the gamut from a light whirring to the above-mentioned whining and occasionally up to a groaning growl, depending on speed and load (ie. fast, sweeping right-hand turns seem to bring out the worst...).

So yeah, it's possible it's a wheel bearing (there are ways to check; see a competent mechanic if you're not sure), but I'd be concerned about the tires. Why were only two replaced? Was there an issue that caused their premature wear and was that issue resolved?
 

·
Premium Member
03 H6 OBW & 06 WRX Sportwagon
Joined
·
17,816 Posts
swap ONE tire with the rear on the same side. See if the sound changes.

(open diffs may allow this to work OK)

center carrier bearings have also been reported to whine when failing.
 

·
Registered
Joined
·
22,835 Posts
My 2009 Outback manual has started a speed related whine, that increases in pitch as speed increases, and independent of whether clutch is in or not.
From reading messages on forums seems it may be a wheel bearing (93000 miles all originals). I'm going on holiday for about 500 miles next week so if it is a wheel bearing I'll leave it until I get back. The one thing I want to be sure of though, is that it isn't the AWD system - I had new tyres fitted about 6 months ago on one axle, the other 2 are about 50% worn - so maybe 1/2" difference on circumference. Would the AWD system cause a whine?
99% of the time this is usually due to low gear oil in the transmission. As the gear oil breaks down it gets thin. Every single MT car I have had would start to leak when the gear oil got thin. Then you would start to get speed related whine. The other spot is the rear diff same exact cause needs the gear oil done.
 

·
Registered
2005 OBXT Limited, VF37, STI intake, 5MT
Joined
·
1,578 Posts
1/4 in. circumference is the limit for acceptable tire size differences. With 6 months with a stressed AWD system, you could be having issues related.

However, driveshaft carrier bearing makes a similar noise. 93k is a little early, but not unheard of
 

·
Registered
06 OBW 2.5, 05 Forester, had 03 H6 OBW
Joined
·
5,936 Posts
Wheel bearings, increase the speed by 2x and the noise pitch increases by 2x.

Anything differential (pinion side) or drive shaft related, the noise pitch increases 4 times as fast as driving speed- 2x the speed begats 8x the pitch.
 

·
Registered
2005 18psi supercharged U5 Outback w/207k+ miles
Joined
·
790 Posts
That's the supercharger... :)

But in follow up to subiesailor's pos, have you checked MT/diff fluid (dip stick kind of hidden on passenger side)?
 

·
Registered
2007 2.5 base 5MT
Joined
·
140 Posts
Failing hubs start as low whine like you describe before getting louder, eventually to jet engine noise. Often you can tell a failing hub by driving straight, then whip the wheel a bit side to side and the whine will drop off when wheels are not straight but once the hubs get really grooved this test does not work. The other area that causes this type of noise (as I unfortunately discovered) is the rear shaft bearing, another known fail point on subies.
 
1 - 9 of 9 Posts
Top