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Discussion Starter #1
~140K, 1 owner, tranny fluid "changed" just this summer at ~135K.

Car vibrates noticeably on mild acceleration, mostly independent of which gear is selected. Vibration is most noticeable in the 20-30mph and 50-60mph bands, though sometimes present at other speeds. Vibration disappears when coasting, and minimized when downshift to higher revs and under full power.

In reverse (with windows open so I can hear) an intermittent scraping noise is sometimes heard and seems to be associated with the rotation of the drive-shaft. The same intermittent scraping noise is heard at slower speeds (sub 40mph, windows down, adjacent buildings for sound reflection) on engine deceleration and again seems related to the speed of the drive shaft.

I've checked the drive shaft for contact with anything, including the flimsy aluminum heat shield between the drive-shaft and the exhaust pipe. No other apparent contact. While lying down on the driveway while a friend drove back and forth the sound is difficult to localize but appears to be from the transmission / drive shaft junction area.

I think the two symptoms are related, but can't be positive. Any ideas?! Thanks!
 

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03 H6 OBW & 06 WRX Sportwagon
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17,711 Posts
if it's drive shaft speed (maybe using some white paint or a piece of orang tape would help confirm?) u-joint and carrier bearing are suspect.

if wheel speed, brake backplate/shield dragging or some kind of stuck caliper or brake pad issue?
 

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03 H6 OBW & 06 WRX Sportwagon
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just a visual clue to help see if rotation really syncs-up with the sound. Seems like you might be able to do this in a driveway.....?

depending on the final drive and gear chosen, drive shaft will turn a lot faster than wheels.


maybe try a search for bad u-joints and carrier bearings? (your car does not seem like a great candidate based on age/miles but = maybe some 'event' happened in its past to cause a problem?)


also, post your location, someone may know a good shop to recommend if this gets too tough for DIY.
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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16,144 Posts
The portion of the driveshaft that slides into the transmission is splined. Perhaps the u-joint right before the spline is going. It has a metal housing near the spline. Perhaps that housing is rubbing on the spline or sleeve as it rotates...or because it is wobbling.
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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I have the same car at 150K my front u-joint went bad and it exhibited similar symptoms. It's hard to determine with the driveshaft in place. I found that after I removed it, I could actually feel the worn u-joint. When I started trying to figure out what it was, I thought it was a bad carrier bearing. Here in the midwest, we don't have a driveline service that can rebuild the shaft and I had to buy a new one at about $475 - ouch!

On acceleration, especially turning, I would get the vibration and noise. Running in straight line and cruising it wasn't noticeable.

I believe I saw where there are some shops on the west coast who can do rebuilds?
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
Joined
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16,144 Posts
I have the same car at 150K my front u-joint went bad and it exhibited similar symptoms. It's hard to determine with the driveshaft in place. I found that after I removed it, I could actually feel the worn u-joint.
Agreed, unless they are very bad...sometimes they appear to be just fine int he car.
 

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Discussion Starter #8
Solved!

Went with a used prop shaft from an '05 2.5xt w/ the 5eat tranny. Running smooth again

Dropped the exhaust for access, definitely worth the effort in my opinion.

Just an FYI, you'll lose a bit of tranny fluid from the rear end of the tranny during the swap.

Thanks for the help everyone!
 
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