Driveline Vibration

Discussion in '2011+ Mustang GT 5.0L Tech' started by J.Kidd, Oct 26, 2019.

  1. J.Kidd

    J.Kidd forum member

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    Started noticing a month ago...and surprisingly it has not gone away.

    Symptoms:
    Part 1:
    First thing I noticed was when I took her out after washing to clear stubborn water off, I noticed a relatively soft "clunk" when shifting (casual shifting, not accelerating too hard). It didn't do it all the time, and if I was more ginger with my clutch engagement, it didn't do it. But, casual acceleration with casual gear changes would result in a noticeable (sound and feel) clunk.

    Part 2:
    The next thing I became aware of was an occasional vibration at speeds over 75. This vibration is not constant, but more cyclical when I feel it. I would feel a vibration for 4-5 seconds then it would disappear for 2-3 seconds, and then return....and this would just repeat.

    Upon experimenting (ie. coasting with the clutch in, coasting with the clutch out), I have determined that the vibration is coming from the driveshaft. Coasting, engaging the clutch or not, does not eliminate the vibration.

    I am suspecting either U-joints or carrier bearing. Aside from CAI and tune, the car is pretty much stock (2011 GT with 80k miles). Anyone have experience with this?
     
  2. Sky Render

    Sky Render Stig's Retarded Cousin S197 Team Member

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    Transmission mount?
     
  3. J.Kidd

    J.Kidd forum member

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    Didn’t think of that! Basically gotta crawl under there and see what moves. But thanks, you gave me something else to look at when I’m under there.
     
  4. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
    56
    736
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    You're on the right track. Raise the car on a lift and check if there's excessive play in either of those areas.
    The u-joint is easy to replace but the carrier bearing is non-servicable and would necessitate replacing the whole driveshaft. Good excuse to get an aluminum unit and save ~20lb too.
     
  5. MasterofDisaster

    MasterofDisaster Junior Member

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    Decades ago I had a terrible vibration coasting in my 1967 notchback, but couldn't find the source until the car was in park on jackstands. The rear wheels turned almost a half turn because the U joints were bad. Changed the U joints, vibration went away. You don't need a press if you have a C clamp that is big and burly enough to install the new U joints.
     
  6. J.Kidd

    J.Kidd forum member

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    Anyone have any idea how much the carrier bearing/bushing is supposed to move?

    U-joints were SOLID. Transmission mount felt good as well. But, the carrier bearing had a good amount of movement to it. It almost seemed as though if I had the room, I could have pulled the rubber bushing up and out of the housing. Also seemed like the entire bushing was pushed forward...in the sense that there seemed to be a recess coming in from the back and none in front.

    Just want to get some sort of confirmation that the play I experienced is excessive before I drop a few hundred on a new driveshaft.

    Thanks for any help.