I've got a problem with occasional ratcheting from the rear axle on my 2000 XJ that has me stumped. It's an XJ D44 with Teraflex rear discs, 4.10 gears, and an ECTED locker; there's a Wilwood proportioning valve on the master cylinder (ABS, but disabled - fuses & relays are pulled).
Symptom: moving off from rest occasionally results in a ratcheting noise from the rear axle. There are no discernible vibrations from it while this is happening. It happens moving straight or in a turn, and typically goes away around 25-30mph. Applying the footbrake slightly or working the handbrake a few times while moving makes the noise stop while the brake is applied, but it comes back when the brake is released until speed is up. Eventually it goes away of its own accord, typically after driving for 3-5 miles, but can come back randomly.
Troubleshooting so far: checked rear calipers; they appear to be working properly. Checked handbrake cable; appears to be working properly. Jacked rear end and turned wheels by hand both forward and reverse with locker engaged and disengaged; no ratcheting and locker appears to be functioning as intended. Proportioning valve seems to be doing its job and does not have a noticeable effect on the sound.
Like I say, it's intermittent and there doesn't seem to be any clear cause as to the sound. This has been going on for a while, too: I had the diffs open a couple of months ago to change the oil and seals and while there were no immediately-visible signs of internal problems, I didn't tear everything down while I was in there. Friction modifier was added at the gear oil change so it should be OK on that score; no oil loss is apparent from either the axle tubes, breather, or diff cover. I don't believe this to be weather-related as it started up late spring / early summer, which was before the diff oil was changed.
Anyone have any ideas? It doesn't seem to be affecting anything, but it's not making me real happy that it's doing it either.
Symptom: moving off from rest occasionally results in a ratcheting noise from the rear axle. There are no discernible vibrations from it while this is happening. It happens moving straight or in a turn, and typically goes away around 25-30mph. Applying the footbrake slightly or working the handbrake a few times while moving makes the noise stop while the brake is applied, but it comes back when the brake is released until speed is up. Eventually it goes away of its own accord, typically after driving for 3-5 miles, but can come back randomly.
Troubleshooting so far: checked rear calipers; they appear to be working properly. Checked handbrake cable; appears to be working properly. Jacked rear end and turned wheels by hand both forward and reverse with locker engaged and disengaged; no ratcheting and locker appears to be functioning as intended. Proportioning valve seems to be doing its job and does not have a noticeable effect on the sound.
Like I say, it's intermittent and there doesn't seem to be any clear cause as to the sound. This has been going on for a while, too: I had the diffs open a couple of months ago to change the oil and seals and while there were no immediately-visible signs of internal problems, I didn't tear everything down while I was in there. Friction modifier was added at the gear oil change so it should be OK on that score; no oil loss is apparent from either the axle tubes, breather, or diff cover. I don't believe this to be weather-related as it started up late spring / early summer, which was before the diff oil was changed.
Anyone have any ideas? It doesn't seem to be affecting anything, but it's not making me real happy that it's doing it either.
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