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Haldex Humming

Discussion in 'A3/S3/Sportback (8P Chassis)' started by rokape, Aug 16, 2012.

  1. rokape
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    rokape Member

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    [Aug 16, 2012]
    Hi!

    On my phone, so to cut a long story short, I have an A3 Quattro 2006 8P2 TDI 2L

    When I accelerate harshly, I get a loud humm (constant).

    When I reach 75mph & in 6th gear, I get a humming vibration, it resonates on and off continuously. Go above 80Mph and it goes away...

    I read I could disable Haldex by putting the hand brake on 1 click, I did this and went for a drive:

    No vibrations when accelerating.

    Only an extremely mild version of the above at 75mph in 6th. Hardly noticeable.

    I then took the handbrake off and BOOM! Vibrations.

    Haldex is shot? Oil change? Filter change? Pre charge pump? Per credit card max out pump? :( sell the car change?

    No errors on VCDS at all.

    Googled the hell out of this one to get this far! Hope someone can help with the above info.

    Thank you!
    #1
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  3. audicruiser
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    audicruiser Audi Heaven

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    [Aug 16, 2012]
    Disable the Haldex with the handbrake on one click????

    What your mileage? Has the oil ever been changed?
    #2
  4. rokape
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    rokape Member

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    [Aug 16, 2012]
    Yup, one click enough to put the parking light on in the dash. I was going to remove the fuse, but someone said it cost them £3k to fix, so decided against that one!

    Mileage is 87k - not been changed as far as I know, no. Would that cause this noise & would changing the oil fix it or has the damage been done?
    #3
  5. audicruiser
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    audicruiser Audi Heaven

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    [Aug 16, 2012]
    I can assure you this doesn't disable the Haldex unit, but you need to get your oil and filter changed as it should of been done twice at that mileage! Every 40k miles.

    There are recent threads on this very subject.
    #4
  6. rokape
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    rokape Member

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    [Aug 16, 2012]
    Ok, but how come when the light in the dash goes off, it starts to vibrate immediately?

    Seems more than coinsidence.

    I will be getting the oil & filter changed ASAP. I saw the other thread but this humming is why I opened my own.

    Would the oil/filter change help you think or is it borked forever now?
    #5
  7. Wicked666
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    Wicked666 Active Member

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    [Aug 16, 2012]
    On the 8L's, the handbrake up used to disable the haldex
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  8. audicruiser
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    audicruiser Audi Heaven

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    [Aug 16, 2012]
    Because the rear discs are clamping the axle and stopping the vibrations when you pull the handbrake.

    Get the oil changed and see what happens. You may of got to it in time...
    #7
  9. rokape
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    rokape Member

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    [Aug 16, 2012]
    I already thought of that ;) I again pulled on the handbrake up to see if it was the disks stopping the humming, but it didn't - I pulled it fairly hard too (bear in mind I was doing 75MPH).
    #8
  10. rokape
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    rokape Member

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    [Aug 16, 2012]
    I will change it, but is there anything else that would cause this? Could the rear drive shafts be mashed / bent or something?
    #9
  11. discostu49
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    discostu49 Active Member

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    [Aug 16, 2012]
    am i tired or am i reading this wrong? U PULLED THE HANDBRAKE HARD AT 75MPH!!!!
    #10
  12. rokape
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    rokape Member

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    [Aug 16, 2012]
    Not quite as it sounded. I applied enough pressure to stop the humming if that were preventing it before, I didn't yank it on or even hard enough to change the speed of the car.
    #11
  13. shariain
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    shariain Well-Known Member

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    [Aug 16, 2012]
    Check your wheel bearings on the rear.
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  14. rokape
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    rokape Member

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    [Aug 16, 2012]
    Will get them checked tomorrow :)
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  15. veeeight
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    veeeight Well-Known Member

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    [Aug 17, 2012]
    Handbrake on signal does de-couple the Haldex (on my Gen 4 unit) and 8P3's.
    So does the brake pedal switch.
    And the ESP on signal.

    All these signals de-couple the Haldex on the Gen 4 unit. Not sure about Gen 2 or 3.
    #14
  16. pat_986
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    pat_986 Member

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    [Aug 17, 2012]
    I have this same fault, and am about to pull my hair out over it.

    My advice is to be very careful before you start shelling out money on " fixing the fault"
    So far, I have been told it was the tires, then a buckled wheel, bent drive shaft, wheel bearing.
    All have been replaced and the fault still persists.
    The next thing I'm about to try is a replacement diff. I've brought it, just need to fit it. Will let you no how I get on.

    The only thing past that all this could be the rear prop/haldex coupling join. Have read a lot on this forum suggesting this is the fault, but the garage are adamant mine is fine?
    I will try and find the links.....
    #15
  17. Smithymartyn
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    Smithymartyn Member

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    [Aug 17, 2012]
    I had a similar fault, so feel yer Haldex 'pain.'

    When accelerating in a higher gear, I had a loud 'booming' noise coming from the rear diff. In the end, I had to have the Haldex coupling bearing replaced, a kind of donut in shape.

    Went to the steelers as had only recently purchased the car from an independent and warranty expired. From memory it was a £400+ job, but no doubt cheaper at a decent independent.

    Good luck, hope you sort it mate
    #16
  18. Dean.no4
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    Dean.no4 Member

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    [Aug 17, 2012]
    #17
  19. pat_986
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    [Aug 17, 2012]

    Yeah, that's one of the threads I read before.
    I took my car to a well known Audi specialist asking them to change this part, they basically said no they won't, as they are so confident there is nothing wrong with the one on my car.
    As said before, they think my diff is at fault. I will change that soon and report back.
    #18

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