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  • Low Speed Coasting Clacking

    Hey gang,

    I've got a strange noise that I haven't been able to diagnose. When I am coasting to a stop from a slow speed (<20 mph) I get a clacking type noise that slows as the Jeep coasts to a stop. The noise remains unchanged when I disconnect the front DS.

    Any ideas what my problem might be?

    Mods that have affected my driveline are:
    4" suspension lift,
    Front alloy shafts,
    Nth tummy tucker,
    Tom Woods rear CV DS.

    Thanks!

  • #2
    Assuming the following:

    1, The noise is there if you coast down and or tip in.
    2. The noise is likely there at higher speeds, but you cannot hear it over the other noises.
    3. You do not feel anything associated with the noise (brake drag, thud, bump, wobble in front or rear).

    Likely suspects.
    Lug Nuts: Check left rear first. 100ft-lbs.
    Brake shoes: Rear brakes may have chunks rolling inside the drum.
    Worn front brake pads: Calipers are backed off a little and the pads are chuckling as the rotor turns.
    Universal Joints - Driveshaft: Grab/Shake/Twist. You would feel a big clunk if you tip in and back out.
    Damaged ring and pinion in dif: Just Empty every pocket
    Bad rear wheel bearings- Dirt but easier than above.
    Bad transfer case/ input end. $$$$
    Front axle universals binding. Heavy steering and low returnability.
    I'm thinking strongly it's lug nuts.

    Try driving along side a brick wall (My favorite is the side of Target down the road), and listen for the noise coming from front or rear, or if pitch changes with steering or throttle input.

    Comment


    • #3
      Those assumptions are all correct.

      One thing I probably should have mentioned though is that the noise is rhythmic and it's speed is proportional to the speed of the Jeep and/or RPMs.

      I'll check the lug nuts, and the calipers...no drums in the rear. All u-joints are new or not spinning (front DS is disconnected). No symptoms with the steering. Is there any way I can check the integrity of my ring & pinion, t-case and wheel bearings without tearing in deep?

      Comment


      • #4
        Andy,

        I know you've probably already ruled this out, but I always end up hearing the rocks I have stuck in my tires when I'm coasting to a stop. Its a clacking sound that varies with vehicle speed and performing a quick FOD check is a lot cheaper than breaking into the ring and pinion.

        Ryan

        Comment


        • #5
          Yeah, checked that just to be safe. I was pretty certain what I would find even before I checked. It's mechanical in nature and the sound comes through the rigid structure into the cab pretty well.

          I wish it were that easy!

          Comment


          • #6
            Check your center caps if they are loose in the center hole of the rim they can click as your tire rotates. I had this on my Cj and liked to drive me nuts till I figured it out. Problem solved with a bit of clear silicone around the inside edge. Rock steady!

            Comment


            • #7
              A buddy of mine had the same noise a while back. So after a long look over of everything we found that the nuts on the universal joints on the rear drive shaft were hitting when the drive shaft was rotating or the jeep was driving. HE did install a 4" rubicon express lift also. not sure if this helps but take a look anyway.

              Comment


              • #8
                UPDATE:

                We took the wheels off the ground today so we could get a good localized listen. Found two issues.

                The first, and probably most serious, came from my manual transmission housing. At idle, in any gear and any transfer case position I can hear distinct rattling noises from inside the transmission. Very pronounced if I put my ear up to the housing. Almost like something is loose in there and bouncing around. At higher speeds it sounds more like a grinding noise, but it's somewhat hard to tell over the engine noise. Fluid level is great, so I am probably going to drain and filter the fluid to see if I get anything. Any suggestions for a filtering mechanism?

                The second issue is on my front differential. With the axle unlocked if I spin a tire I can hear a rhythmic thwup thwup thwup type of sound from the diff. Of course it slows as the tire slows. When I lock the axle the noise disappears completely. It's a quiet enough noise that if the engine is running, you can't hear it at all. If I spin a rear tire, locked or unlocked I get no noise at all. Any idea what this noise might be? I'm not 100% convinced it isn't normal.

                Comment

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