Clunk Clunk Clunk
 

1996 XJ Cherokee Pre Update 4.0. 160k kms. Apologies for the long post.

Hey all, I've developed a bit of a problem that I'm struggling to pin point. Hard to explain, but I have a binding type knocking happening in the front of the Jeep when in 4wd only. The sound doesn't occur in 2wd/without front shaft. It is much more pronounced when close to full steering lock in 4wd. Full lock steering in 2wd doesn't replicate the same knocking/clunking.

So this is what I've done to troubleshoot the issue so far:

- I'm an amateur but felt to me like axle uni's. Since I don't think the uni's have ever been touched I uninstalled the front axles and inspected the u joints. They seemed ok, but took them to be replaced professionally anyway.
- Checked the front wheel hubs, they also seemed ok but one had a little bit of play in it. Decided to replace these as well just in case.
- Inspected the front driveshaft, the diff end uni seemed ok but not great, one of the plastic boots had a crack in it so I replaced it. The double cardon joint was very dry feeling and notchy when rotating it around. Didn't tend to this end of the driveshaft at this stage.

After putting it all back together went for a test drive, and the knocking was still present. :mad:

- Took out front shaft again, knocked out the uni in front of the centring bearing and it seemed ok. Then took the centring bearing out and all the needle bearings just fell out and it was dry as in there, and notchy. It was cactus, the bearing was just floating around in there, and most likely the cause of an angry sparrow type noise I've been afflicted with lately. The other uni in the joint seems fine, but I will replace when I receive a new centring bearing.

Then

-Since I have a SYE and have a front driveshaft in the rear, I decided to place the rear shaft in the front for a test drive. All uni's in this shaft feel fine. Went for a test drive and this time you can hear the same knocking all of the time, and louder when at full steering lock. Hmm...
-Jacked the car up and placed the front on jack stands. Took the hat off the front diff and expected to see metal bits come out. Nothing. No shavings. Checked all gears and there are no teeth missing. No movement in the pinion at all. When moving the wheels, there is a little bit of play in the axle gears but nothing I would think was out of the ordinary.
- I found I can replicate this noise while the front of the jeep is on jackstands. Had a mate place the car in 4wd and select drive, and the noise would come about again at close to full lock steering only. It was hard to pin point the origin of the knocking but I could feel backlashing when feeling the base of the D30, and at the transfer case.
- Dumped the fluid from the transfer case to see if I could find anything... nothing, no metal and the fluid looked as good as it did when I put it in there 6 months ago.

Few, so that's where I'm at. Could this be a chain issue in the transfer? Anything else I should check or try? Had my heart set on heading to Fraser for the first time in a couple of weeks but that is looking unlikely. Thanks in advance for any input.

I'm keen to here some input from experience. I had this happen to me the other day on the trail, especially when getting the front left wheel drop into ruts. Big clinking and binding. Keen to hear a solution.

Forgot to close this off since I found the issue and someone may benefit.

Ended up being a trashed center bearing in both of the driveshafts I was trying. Have replaced one in one shaft, and sourced a second hand driveshaft for the other. Drive line is now quieter than a mime convention.

Is that the bearing between the 2 unis on the double cardan shaft?

Indeed it is