940 Turbo knocking from drive

Discussion in 'Volvo 940' started by Tony Stanley, Oct 19, 2003.

  1. Tony Stanley

    Tony Stanley Guest

    My 940 estate seems to be giving out knocking sounds from the rear under
    hard acceleration in 5th from 60-75 or so. It sounds like small bumps on
    the road a few times a second or so, but is definately linked to
    acceleration and doesn't occur at different revs on the same piece of smooth
    road.

    It does get a bit of a hammering, have I worn out the universal joint, or
    the support bearing or something?

    1995 940 SE 2.3 Turbo estate, 115,000 miles
     
    Tony Stanley, Oct 19, 2003
    #1
  2. I would first check clearance around the exhaust pipe and make sure all
    rubber devices are in place.
     
    Gunnar Eikman, Oct 21, 2003
    #2
  3. Tony Stanley

    Tony Stanley Guest

    The exhaust doesn't go anywhere near the drive shaft at the rear, and is
    well secured. I'm faily sure the noise is comming from the rear, and I
    think I would know the difference, its just not that sort of noise.

    Its getting worse now, or I am looking for it more. Full tilt in 1st now
    feels very rough.
     
    Tony Stanley, Oct 23, 2003
    #3
  4. I did not mean that the exahaust hits the drive train, possibly the
    underbody of the car.

    If you do have a mechanical problem, there are several candidates:

    The Hardy disk (rubber thing) at transmission rear end. I have read that
    these get worn and cause vibrations, without loooking noticeably bad.
    They are a bit expensive to replace "just-in-case". I never had one fail
    myself.

    The support bearing, or rather its rubber housing. Same thing. Never
    happened to me. One bearing went bad, but it created noise, a whining
    sound like circular saw or so.

    U joints. When they get worn (or jammed) they cause vibration and make
    noise, although in my limited experience at all loads. I had one jam,
    causing vibrations at highway speed. Sound and vibration was pretty much
    independent on load. Same when coasting or accelerating.


    --
    Gunnar

    240 Turbo Wagon '84 200 K Miles
    940 Wagon '92 150 K Miles
    on Swedish roads
     
    Gunnar Eikman, Nov 3, 2003
    #4
  5. a bad u joint would be my guess...does the
    spped of the knocking change w/the speed of the car?
     
    ~^ beancounter ~^, Nov 4, 2003
    #5
  6. Tony Stanley

    Peter Milnes Guest

    Also check your engine and gearbox mounts.

    Cheers, Peter.

    : a bad u joint would be my guess...does the
    : spped of the knocking change w/the speed of the car?
    :
    :
    :
    :
    : > I did not mean that the exahaust hits the drive train, possibly the
    : > underbody of the car.
    : >
    : > If you do have a mechanical problem, there are several candidates:
    : >
    : > The Hardy disk (rubber thing) at transmission rear end. I have read that
    : > these get worn and cause vibrations, without loooking noticeably bad.
    : > They are a bit expensive to replace "just-in-case". I never had one fail
    : > myself.
    : >
    : > The support bearing, or rather its rubber housing. Same thing. Never
    : > happened to me. One bearing went bad, but it created noise, a whining
    : > sound like circular saw or so.
    : >
    : > U joints. When they get worn (or jammed) they cause vibration and make
    : > noise, although in my limited experience at all loads. I had one jam,
    : > causing vibrations at highway speed. Sound and vibration was pretty much
    : > independent on load. Same when coasting or accelerating.
     
    Peter Milnes, Nov 5, 2003
    #6
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