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Clicking/Clunking Sound

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  • Clicking/Clunking Sound

    Hi. I have this clunking sound which occurs when I am coasting to a stop. It continues from a couple of mph and gets louder (but slower) until Growler stops. It is most consistently heard when the clutch is in, or it is out of gear, and goes-away when the transfer case is disengaged. It is very audible in the cab, so I was thinking it was in the transfer-case, but this was recently rebuilt. No difference in 4WD. There is a fair bit of play in the the driveline, so instead, I think some splines are worn-out. Indeed, the splines on the rear wheels driven by the half shafts ("drive gear?) are showing a fair bit of wear (there are ridges of about 1/32" where the mating-surface with the shaft ends), so I'm replacing those. There is a small amount of play in the drive shaft splines too, but I'm going to start by just replacing the drive gears on the rear wheels.

    I don't remember the problem before I pulled the engine and rebuilt it a few years ago though, so maybe I am off-track. Nothing-else in the drive-train was replaced when I rebuild the engine. New u-joints did not solve the problem.

    Anyone run into this before??

    Thanks a bunch.
    Last edited by Always a Rover; 05-21-2021, 11:39 PM.

  • #2
    So it is ground speed related and not engine speed related? Is front wheel drive engaged? Either with or with out free wheeling hubs. Overdrive?
    1960 109 w/ 200TDI
    rebuild blog;

    You don't see faith healers working in hospitals for the same reason you don't see psychics winning the lottery.


    • #3
      Remove the front drive shaft and test drive. The slip joints in those are known to wear out.


      • #4
        HI. Thanks. I was hoping this was going to be as simple as "Oh-yeah, it is this." Okay.

        Yes, it is ground-speed related. Revving engine alone has no effect. It is the same with or without 4WD engaged, or the freewheeling hubs. It is not OD dependent. Since it is not 4WD related, how could it be the slip joints in the front shaft???

        Sometimes you just have to take things apart and look, I realise. Then it makes sense.

        What I do know is:
        - when the rear wheels are slowly turning while not being driven by the motor, the noise occurs, gradually becoming louder and more percussive as the vehicle slows to a stop
        - you can feel the vehicle lurching a bit as the clunks occur, or maybe a bit before, like something is binding, then letting-go
        - the sound seems like it is coming from directly below the floor
        - it makes no difference at all if the gears - any gear - are engaged (with the clutch in) or not
        - if you are in gear, and let off the gas, the noise begins to appear, but it is much louder and consistent if the engine is not driving the wheels
        - there is maybe a 1/2 inch rotational play in the driveline, so some of the splines are worn?
        - there is no "clunk" when shifting gears
        - when the transfer case is disengaged, there is no resistance to the wheels driving the half-shafts, diff and main drive-shaft, so.... splines are not binding???
        - the parking brake was recently re-adjusted, works well, and made no difference
        - there is no whining noise in the diff, which I am told is a good reason to rule that out

        I have a mechanic looking at it, as I am too busy these days, and he is also changing a bunch of seals etc.... the spline idea was his.
        I will have him check for metal-shavings in the diff, transmission and transfer case.
        I hate to say it, but I think it could be in the transfer case

        I'm on the verge of letting-go of backlash in the splined connections, I don't think the play in the driveshaft is the cause, although this may need addressing, as I have plans to pull a trailer up hills with it, and am upping the HP by installing fuel-injection - I'm not sure how much play in the driveline is normal, but I should think some in the diff is normal.

        I have found a few mentions of something similar on other forums, but no consistent solution. One person found the parking brake was the source of something similar, for another it was a worn shim in the transfer case (both Defenders). There were a few tests/checks mentioned, like alternately disconnecting one drive-shaft. No one mentioned that disengaging the transfer case caused the noise to go away....

        Thanks. Just writing it all down helps. There are no such thing as dumb questions/suggestions. I'll update.
        Last edited by Always a Rover; 05-22-2021, 08:03 AM.


        • #5
          Quick and easy, pop the transmission brake drum off and look for something(bolt) knocking around in there.
          1960 109 w/ 200TDI
          rebuild blog;

          You don't see faith healers working in hospitals for the same reason you don't see psychics winning the lottery.


          • #6
            Good idea Gene. Actually many times I've found the output flange nut that holds the parking brake drum assembly on to be very loose. Also pull the PTO cover on the transfer case and check the nut on the trans output shaft. Just last week I found one of these finger tight.


            • #7
              Hi - I'll have a look under the PTO cover, but no-dice on the park-brake fix.


              • #8
                If anyone has mentioned universal joints, I missed it. Sounds like classic u/j to me!
                Today is a good day to die........
                .......But tomorrow would be better...