87 740 wagon loud thud/knock when accelerating

Discussion in 'Volvo 740' started by g13, Dec 4, 2006.

  1. g13

    g13 Guest

    hey,
    about 50% of the time when i accelerate (and usually during heavy
    acceleration from complete stop in 1st gear), i hear and feel a heavy
    knock or thud coming from the rear (differential, maybe?). it feels like
    as if a heavy object like a bowling ball rolled back due to the
    momentum and hit the back of the trunk.
    any ideas?
    g13
     
    g13, Dec 4, 2006
    #1
  2. The center support on the drive line is weak, let's the drive line hit the
    exhaust pipe. At least that's what happened with our 2000 XC 70. Had to
    replace the drive line, couldn't get the center neoprene mount separately,
    according to our technician.

    Dale
     
    Dale_Peterson, Dec 4, 2006
    #2
  3. g13

    Tony Guest

    The 740 has a more robust drive train (since it has lasted nearly 20
    years in this case), but then all the modern Volvos are made from rubber
    bands and matchsticks. I don't know what I buy if my 940 becomes
    uneconomical to repair (hopefully it will last until the oil runs out
    and I'll convert it to electric).

    Anyway, its probably a loose bush at the rear, holds some arm in place,
    something is colliding under rotation. Support the car on axle stands
    or ramps and take a pry bar underneath and leaver each bush to check for
    excess play.
     
    Tony, Dec 5, 2006
    #3
  4. I HAD THIS WTH MY WIFES CAR A GEARBOX MOUNT WAS WORN OUT REPLACE IT
    MARKING WHICH WAY IT GOES IN .I didnt and had to put it back in right
    side up oy voy a dumb goy !
     
    John Robertson, Dec 5, 2006
    #4
  5. Have you checked that there isn't a bowling ball in the trunk?
     
    Steve Shuttleworth, Dec 6, 2006
    #5
  6. Please tell us which on it is as I believe its the gear box mount to the
    frame and I have two 740 turbos .
     
    John Robertson, Dec 7, 2006
    #6
  7. SORRY THAT DIDN'T MAKE MUCH SENSE CANT BELIEVE I WROTE IT, BUT TRY OUT
    THE MOUNTS ON THE GEAR BOX ANYWAY !
     
    John Robertson, Dec 12, 2006
    #7
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