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Thread: Slight vibration at 3500 revs

  1. 25th November 2009, 09:37 AM #1
    ytt105
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    Slight vibration at 3500 revs

    1996 4.6, 180k P38a

    When the revs get to between 3500 and 4000 there is a vibration from the driveline.

    I checked the rear driveshaft and found that I could get a knock, in each direction, quite easily. But only one knock, and I couldn't see any movement.

    However, I'm assuming this is enough to tell me I should replace all four unis and hopefully this is the vibration.

    Are aftermarket unis OK, or should it be genuine only? Where do I get them?
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  2. 25th November 2009, 09:52 AM #2
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    p38arover
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    Is it RPM related or driveline? What happens if you change gears to change RPM at that road speed?
    Ron B.
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    Previous: 1983, 1986 RRC; 1995, 1996 P38A; 1995 Disco1; 1984 V8 County 110; Series IIA



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  3. 25th November 2009, 03:36 PM #3
    ytt105
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    Yes its RPM related, not road speed!

    Don't tell me its the flex disc, that's not what I want hear!!

    I'd rather change the unis!
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  4. 25th November 2009, 03:43 PM #4
    Rangier Rover Guest
    Quote Originally Posted by ytt105 View Post
    Yes its RPM related, not road speed!

    Don't tell me its the flex disc, that's not what I want hear!!

    I'd rather change the unis!
    Flex plate is plausible.. I hope not for your sake.
    My rangie developed a vibration at high RPM and turned out to be a spark plug breaking down. Took a wile to find it to I may add.
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  5. 26th November 2009, 10:56 AM #5
    mike 90 RR Guest
    If you hate the Flex plate theory ....
    another couple to add to Rangier Rover's list .... Check the condition of the rubber engine mounts .... and the Harmonic balancer hasn't moved on it's rubber bushing

    Mike
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  6. 27th November 2009, 11:20 AM #6
    Hoges
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    Quote: "Are aftermarket unis OK, or should it be genuine only? Where do I get them?"

    I got some after market ones from Britparts UK for about $7 each...THEN I did some research and found that the special Hardy Spicer heavy duty version for the Defender also specified for the P38... varying in price from A$60-75 EACH . THEN I discovered the good folk at Land Rover Parts and they were delivered to Bris for about $50 each. The difference in quality is readily apparent
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  7. 30th November 2009, 04:36 PM #7
    ds23man
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    Maybe your viscofan is on the way out! Can cause serious vibrations when you rev up.
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  8. 30th November 2009, 08:06 PM #8
    mike 90 RR Guest
    Quote Originally Posted by ds23man View Post
    Maybe your viscofan is on the way out! Can cause serious vibrations when you rev up.
    Not a bad call, actually ...

    Check your plastic blades for splitting ....
    Mike
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  9. 1st December 2009, 04:54 AM #9
    ds23man
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    It is very easy to check, take it of and rev your engine up!

    Gerhard

    PS If you see some progressing woble in the outer rim when you rev up, it is out!
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  10. 2nd December 2009, 09:40 AM #10
    ytt105
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    I've changed the fan and the viscous unit, there were a couple of small 'nicks.
    It helped a little bit, but the vibration is still there. You really don't want to rev that high!
    I'll have a look at the engine mounts and balancer this weekend.
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