Whining noise when decelerating

Discussion in 'Modifications And Maintenance' started by j4ngl35, Nov 3, 2009.

  1. j4ngl35
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    j4ngl35 Well-Known Member

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    Last night on my way to work, there was a quite prominent whining sound whenever I would slow down while in gear (5th was the worst, just about only happened in this gear). Also, if I was accelerating and shifted past 3,500 RPM, give or take, it would briefly make the same sound then during the shift. This morning it wasn't as bad, but it was definitely still there.

    Should probably be noted that at some point yesterday before I left for work at 9:45 pm, my dad borrowed my car and ended up running over a deer carcass that hadn't been cleared off the road. Couldn't tell anything was damaged by looking at the car, though there was some blood and hair on areas of the undercarriage. Could running over the dead deer have damaged something that's causing the whine?

    Thanks for the input!
     
  2. turbo_turtle
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    turbo_turtle Well-Known Member

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    Check the prop shaft carrier bearing.

    ~Dan
     
  3. j4ngl35
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    j4ngl35 Well-Known Member

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    Did some looking for a bit on this and didn't find much, though what I did find very possibly could be my problem. What sort of PITA will I have to go through to fix it if that's indeed what it is? Is the Subaru prop shaft carrier bearing all one piece with the driveline as with some other manufacturers? Sorry if this is a dumb question, it's the first time I've heard that part specifically referred to and addressed.

    Thanks for the info
     
  4. Mr. Derek
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    Mr. Derek Well-Known Member

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    Where does it sound like the noise is from? Transmission or further back. My deceleration noise was further back and I ended up putting a new rear diff in. They thought the gear lash was set wrong at the factory causing it to wear improperly.
     
  5. AWDimprezaL
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    AWDimprezaL has more posts than you

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    The driveshaft is not available in peices, so if its the carrier bearing, its the entire driveshaft.
     
  6. j4ngl35
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    j4ngl35 Well-Known Member

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    It seemed to me to be coming from the transmission, but since yesterday it's hardly been making the sound, and this morning on the way home from work it didn't do it at all. Could this possibly be attributed to cold weather? I've clearly got no idea, lol.
     
  7. FuJi K
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    FuJi K Well-Known Member

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    OMG another center diff fallin apart!!!

    ^^^^that's my guess
     
  8. j4ngl35
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    j4ngl35 Well-Known Member

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    Err...you serious? I hope that's not the case...:eek3:
     
  9. j4ngl35
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    j4ngl35 Well-Known Member

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    Been doing a good amount of research, reading lots of threads about issues similar, if not exactly the same, as mine. Just to reiterate, my car is making an obnoxious whining noise with light throttle application (not quite maintaining steady speed) or deceleration. It is most prominent before/after 60 mph (and in 4th-5th gear), but doesn't seem to be affected by whether or not I'm in gear. I am able to hear the sound at pretty much any speed, though the slower I'm going, the quieter it gets until I just can't hear it anymore. There's no harshness or clunking/grinding that some people have described, and no issues when making sharp turns like people have had with a bad center differential. Basically it drives the same as it always has, but now there's a loud, annoying-ass whining sound that makes me afraid to have any fun while I'm driving it.

    Came up with a few possible solutions while researching, let me know what you guys think. :)

    A.) Check tire pressure and adjust the front tire pressure to be a few psi higher than the back, this seems to be a pretty common fix, though some people think this could do damage in the long run. (Edit: I did notice a couple days ago that one of my front tires appeared to be a little lower than the rear)

    B.) Overfill the gearbox with oil...

    C.) Stop by the dealership and ask about this, which seems to be a fix for exactly the problem I'm having.
     
  10. turbo_turtle
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    turbo_turtle Well-Known Member

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    A) The front tire pressure should always be higher than the rears. In a WRX, 4-5 psi higher in the front is a good thing and is recommended from the factory. Check the recommended tire pressure listed on the door jam.

    B) This is very bad, do not do this. Overfilling the gearbox is by far much worse than having it underfilled. Overfilling it won't solve anything. Changing the fluid is the only way to quiet down the gearbox noises.

    C) I doubt this is your problem, but it could be. The SB is referring to the rear differential rear outrigger bushings. They are pretty tough to begin with and would take years of abuse to wear out.

    ~Dan
     
  11. j4ngl35
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    j4ngl35 Well-Known Member

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    Thanks a bunch for the info turbo turtle! I definitely thought the gearbox overfilling was kind of sketchy, thanks for clearing that up. I picked up a tire pressure gauge today and checked the tire pressure...kind of regretting having my Kumho's mounted at Sam's Club now. All four tires were reading at 24 psi...recommended was 32 for the fronts and 29 for the rears. Would there be a different pressure recommendation for my Kumho Ecsta ASX's over the stock tires? They're the same size as stock, but I know how stuff like this can vary.

    Anyway, I changed the pressures to 32 (give or take .1 psi) in the front and 29 in the rears (again, give or take .1 psi) and didn't notice any change in the loud whining upon deceleration. This is really starting to piss me off...she drives fine but I HATE this noise. Going to take her to the Subaru dealership today and have a mechanic ride with me to see what he thinks.
     
  12. j4ngl35
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    j4ngl35 Well-Known Member

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    Got an appointment setup for Thursday to have a mechanic take a ride in my car. Set my tire pressure to 33 psi in front and 30 psi in the rear, and after a while of driving I'd say the noise is actually worse than before. Kind of don't even want to drive it right now, I'm very anal when it comes to my cars and listening to that horrible metallic whining drives me nuts, especially since I don't know if something is really wrong or not.

    Thursday can't come quick enough.
     

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