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Thread: Odd Helicopter Noise 01 XJR

  1. #11
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    I should note that when I say helicopter noise, when it's at its slowest, you can hear the noise as an individual rotational knock. It almost sounds like the gentle bubbling/popping of an exhaust. It's audible most at 20-30mph under load, and at motorway speeds under load it becomes a proper whirring noise.

    It's definitely not anything caught between shield and disc, and I don't think the disc is contacting when it shouldn't. I've had the car up on stands twice now, and you simply cannot hear anything untoward when turning the wheels by hand, or listening to them as the engine turns them when up off the floor. Unless of course you're inside the car.

    I'll be greasing the drive shaft nipples as a matter of priority, and I'm starting to suspect the diff in some way. Don't really know where to begin seeing as I can find no play anywhere! I was hoping to find signs of a bearing gone obviously awry, but no.

  2. #12
    Senior Member Andy K's Avatar
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    once you have greased the nipples,

    you could drain the diff, check for metal objects in the oil and put new oil in if no large chunks found
    XJR 2001 Pacific Blue
    Range Rover Sport 2005 Red 2.7 TD

  3. #13
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    An update, and not a good one.

    The noise become progressively worse, so I planned to grease the UJs this evening. Unfortunately during the prep I was able to pinpoint the noise, and it is coming from the diff. I can hear and feel a rhythmic knock coming from within it that becomes a whirr as the wheels turn more quickly.

    From brief research this feels as though something has gone nastily awry with the teeth in there, so I'm not sure there's any point bothering with a diff oil change. Straight on to looking at how I can go about replacing the diff. I've had a look at the following thread and it sounds just about doable on the drive with a couple of people and plenty of stands, so this may be the route I take: https://www.jaguarforums.com/forum/x...ent-diy-44442/

    Any experience in this matter would be welcomed!

  4. #14
    Senior Member Andy K's Avatar
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    it can be done on a driveway.

    don't know if the rear suspension has to be removed complete, but if it does......

    loosen rear wheels.
    jack rear body up on chassis
    mark propshaft position. probably not required in your case.
    Loose prop bolts. This is the most difficult, as you need to lock it, and then rotate round to do the next bolt.
    remove rear wheels
    I think the bottom arms may need to be removed to release springs??? (mark bolt possition below wheel as suspension allightment)
    Remove brake calipers and prop them on something
    disconnect handbrake cable in middle.
    unplug ABS cables.
    loosen dampers at the bottom only
    lower it down using a jack.

    It was 15 years ago, so probably forgot something.

    Drive shafts have shims to adjust camber, so don't mix them up.
    XJR 2001 Pacific Blue
    Range Rover Sport 2005 Red 2.7 TD

  5. #15
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    Cheers Andy. That seems to tally up with everything else I've read.

    I've ordered a new diff and hoping to get this done next weekend. One of the biggest jobs I've ever done but I'm reasonably confident! Can anyone think of any areas in which there might be breakages or any single-use nuts that I need to think about? The only ones I know of in the area are the hub nuts but they don't need to come off.

    Would people also be interested in photos of the job being done?

  6. #16
    Senior Member Andy K's Avatar
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    can't think of any consumables (apart from diff oil)

    WD40 or similar handy

    sometimes good to hammer/tap sockets onto nuts before attempting to undo to prevent things rounding off, but might not need that on the jag
    XJR 2001 Pacific Blue
    Range Rover Sport 2005 Red 2.7 TD

  7. #17
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    Very similar noise on my 960 Volvo many years ago, a helicopter resonating noise, couldn't for the life of me find the fault. took it to volvo, up on the ramps and shaking the exhaust caused loose stones to drop out, just a thought
    56 plate S type R

  8. #18
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    Slight update - spent most of Sunday working on the car. The job is certainly a tough one.

    Spent a long while getting the car high securely to be able to use a long bar on the jurid coupling bolts. Took a while but they're all loose and ready to come off. Ran into a couple of issues however, but they shouldn't be too difficult to resolve.

    Firstly, the bolts that attach the top of the spring mount to the body require extra deep sockets to access the nuts, which I didn't have. Secondly, the W-shaped bracket that supports the rear of the diff/subframe has four bolts - either top or bottom pair look like they can be removed to detach the frame, but typically, the bottom ones have too little space to get a long bar with a socket in, and the top ones (which are the ones most people seem to remove looking at pics) are so rusted that the bolt heads have just rounded off.

    Will get there eventually!

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