XC-70 driveline "thunk" sound/feel... others get it?

Discussion in 'Volvo XC70' started by K Bourke, May 19, 2006.

  1. K Bourke

    K Bourke Guest

    I'm six months into owning a 1998 XC-70 with 176,000km on it which manifests
    two similar driveline behaviours:

    1) At a stop with foot on brake for more than a few minutes, I can almost
    always get a minor "bump", which feels as if someone has tapped me from
    behind with their front bumper..... no movement, no dip in the tach, and
    this has happened again in particularly long stops for gridlock. Has been
    doing this the whole time I've had it, and

    2) For the last several days, I've gotten quite a "thump" which seems to be
    from the drivetrain, but occurs while cruising between 80-100km/hr. No
    acceleration, no kick-down, just steady load/speed. The third time this
    happened, the driveline seemed to slip for a second, before catching back
    up... but I was unable to see any change in the tach or speed..... These
    episodes last only an instant, and give the impression I've run over
    something (but with only one wheel/thump). Tranny functions crisply through
    anything I throw at it otherwise. Other than startling me, there seems to
    be no other effect.

    Tranny was flushed completely at 162,000km.

    Dealer had car in shop and on the road today... no abnormal codes, performed
    flawlessly on the test-drive. Replaced the LF wheel-bearing, which was
    likely coincidental, and *did* note the lower engine mount to be separating
    (I think this an unlikely cause...).

    Any ideas/experience from the cognoscenti ?


    K Bourke, May 19, 2006
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  2. You could have hit the nail on the head with the rear engine mount. I used
    to get the same effect on an old 245 and it turned out to be an engine
    mount. I imagine with the complex transmission on a XC all would have to be
    pretty 'spot bollock' to be OK.

    Alistair Ross, May 19, 2006
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  3. K Bourke

    K Bourke Guest

    Lord.... do bollocks *have* spots????? Not on this side of the Atlantic, I
    assure you....LOL

    Thanks for the advice!

    K Bourke, May 20, 2006
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