Carrier bearings toast but need more info.

98 xj, chrysler 8.25 rear, 4.10 gears, posi (clutch type).

Posted lots of threads about this before, but something's finally changed!

So I've got this clunk. Yea, I know it's "they chrysler clunk" and I know "it's a Jeep thing" and I know "you should get a prius" but I never accept any of these answers so while I thank you for your time, I'm not interested in either response. I want a fix.
As always, clunk when hitting or releasing the gas. Yes, it's definitely the diff, I've checked and everything else is tight.

So today on the way back from a few hundred km trip, I noticed the diff was getting awfully hot. It normally doesn't seem to get above ambient temp but today I couldn't hold my hand on it. Got home and as I turned the corner to park, it made some horrible deep rubbing/grinding noise. Not metal on metal, but more like clutch binding (well, actually the clutch slipping) due to insufficient (or too much?) friction modifier. But, I haven't changed the oil today so I'm guessing either water intrusion or heat has changed the viscosity of the oil. The oil seemed sorta green.

Tests and results:
* Trans in reverse, t-case in 4L, lift one wheel off the ground - The wheel can spin about 1/4" before the ring gear moves. Once the ring gear moves, the pinion moves deadly. The slop is somewhere from the axle splines to the carrier. May be the splines themselves on the axle or the carrier or both are worn?
* Trans in neutral, t-case in neutral, lift one wheel off the ground - The wheel behaves exactly the same, as it should because the posi is grabbing, and trying to transfer power to the wheel on the ground. If I really reef on it though, I can spin the wheel by hand and there's my new grindy sound. So ... I'm guessing I shouldn't be able to overpower the posi by hand right? Worn plates or friction incorrect?
* All neutral, both tires in the air - Spin one wheel, and the other spins the same direction as it should. If I quickly stop one wheel, the other keeps moving another 1/2-3/4" before the clunk.
* Drop it all back down and start hitting the carrier. Ho-shit the right side of the carrier can be pried up about 1mm. I'm guessing this is my carrier bearing failing yes? The left side (ring side) doesn't seem to lift or have any up/down play. I can however, pry the carrier to the left about 1mm. Does not move to the right at all.

So a few questions.
1. Where the hell is the posi clutchpack? It doesn't seem like there's any room for it anywhere. Is it that small bit to the left of the ring gear that's about 1/2" wide?
2. What's everyone think? Time for a whole new carrier, and posi? The bearings and clutch discs are cheap, but if I've got play between the axle and carrier splines, are the spines on one the axle more likely to wear than the carrier, or are they going to wear pretty much as a set? Is there something else between the axles and the carrier that might cause this play? Spiders looked good and didn't seem to have any play. I guess I don't really know what the axle splines connect to first. Someone chime in?

Were the 4.10's original to the axle assembly, or did you swap parts with a 2.5L?
Did you (or anyone else) remove that carrier from the axle?


There should be absolutely ZERO side to side play on the Carrier. If there is, either the bearings are trash, OR, ""Someone"" failed to set the carrier preload and gear backlash when they assembled it.

So why's the LSD making such a horrible noise all of a sudden? Is my oil contaminated?

The gears were installed by the previous owner, who I know for a fact was drunk and or retarded when he did any work to the Jeep. ie: he forgot to tighten any of the control arm bolts, or trackbar mount bolts... So I assume anything he's touched is probably wrong. That said, 4.10 gears were installed under his ownership and I wouldn't be surprised if he did it himself (incorrectly).

So carrier bearing... side to side might mean backlash, but what about up and down? Doesn't that guarantee we've got a bad bearing?
Why's the clutch making noise all of a sudden?
Why's the diff heating up so much when normally it runs cold?

Oh yea. If I put the truck in gear (turned off), and rock it forward/backward, the noise is horrible. There are two distinct noises. First, we get the clunk, then shortly after we hear the grinding noise.

Preload is the amount the bearings are loaded.
The bearings are tapered like a cone. If the preload is wrong, or they are worn, you will get both left to right and if loose enough, up and down motion.

Your LSD clutches are the very least of your problems.

Suggest you dissasemble it and find out whats worn out/replace it.
Then put it together correctly.

Also:
Check you pinion preload and bearings.
Look the gears over real good looking for abnormal wear.

Okay, so I'm sorta in a shit situation as the Jeep is my only vehicle and I cant' get to my welder without it.
I've always heard that once the carrier comes out, it doesn't just "go back in" without lots of adjustment, but if I'm not actually modifying anything, can I safely remove the carrier for a proper inspection, and re-install it and expect it to survive a little while?

I've got the case open now and I'm pretty sure the only problems were bad gear oil (contamination from something?) and the carrier bearing preload. The clunk has never got better or worse and aside from the ever-persistent clunk and the clutch noise, there doesn't seem to be any other noise other than a very slight whine on heavy acceleration and deceleration.
I just can't wrap my head around why removing the carrier would mean I couldn't just bolt it back in and expect it to work about the same as it did before. Am I missing something?

I've gotta get to my welder which is about 100km away but don't wanna do the drive if i've got any chipped spiders, but cant' see all the spiders without removing the carrier. Don't wanna remove the carrier if I won't be able to reinstall it to get to my welder. Sorta catch 22 right?

Is it safe to remove, inspect, make no changes, and put back in, or should I just try some fresh gear oil and drive to my welders?

on an 8.25 side to side adjustment of the gear meshing is done buy turning adjusters that are held in with the carrier bearing caps. once the carrier comes out it will need to be re-set up when it goes back in.

Well, while I value everyone's input and I know this is dumb, I just adjusted the adjusters by hand with a small punch and hammer. Just tightened till the carrier was lightly snugged in. There was a tonne of play in the carrier bearings before, so there was no pre-load at all. I figure I've gotta be in better shape now than before.
Took it for a spin and the whine is gone (at least below 60km/h), most of the clunk has disappeared, and the grinding around corners has cleaned up. Sounds like I need a little more friction modifier.

That said though, due to my 6.5" lift and a lot of the rear lift coming from shackle drop, I could only get about 1.5L (3 pints?) in there without lifting the ass end up at least 3 feet. Couldn't do this as I don't have ramps and my bumpers off, so I drove it down a steep hill and topped up the last 500mL (1 pint?) from there. Looked like the diff was about level there and it worked like a charm.

While I was filling up the rest of the oil though, I noticed that the oil in the diff was bubbly and seemed to have a greenish tinge. Is this normal?

After swapping the auburn lsd into the dakota 8.25" last week, I can confirm that there is play between the axle shaft splines and the side gears.

See, and while that seems to be "normal" I'm not sure it's "intended". I suspect a new set of axle shafts or side gears would clean that slop right up

I've come to the conclusion that "Chrysler clunk" is easily fixed in all cases, and that people are just idiots. Wait, I didn't JUST come to that second part, but the first part is new to me

Seems to be the correct way to trace "CC" is as follows:

First, verify the clunk is in your diff by isolating it from the t-case.
1. Disconnect drive shaft from axle, put trans in reverse and t-case in 4L.
2. Give the DS a spin. There should be some play, but shouldn't clunk.
3. Give your pinion a spin with both back wheels on the ground. There should be no play. Found lots of play? Clunk is in the diff. Put your DS back on.

Diff check. Isolate all components and check for play/clearances:
(Open up your case first).
1. Axle shaft splines to side gears. - Lift one wheel off the ground and spin the tire back and forth. If you've got clunk, spin it slower and in smaller movements while watching the side spider gear. Check if wheel movement translates into spider gear movement. If there's any play, replace axle shaft or spiders.
2. Side gears to top gears. - Assuming no play between axle and spider, turning the wheel should engage side gear with top gear, with pretty much no play. Again, find play and replace spiders.
3. Top gears to carrier. - Top gears often wear on the inside where they connect to the carrier. If top spiders move and carrier doesn't... Tada.
4. Carrier to carrier bearings. - Carefully use a pry bar to try to lift the passenger side of the carrier. It should not lift at all. Also pry (very lightly) between the carrier and the bearing cap to check for side to side movement. There should be none. If there is any movement, you either need to set your carrier bearing preload or your bearings are toast. You can set carrier bearing preload the wrong way (like I did) successfully if you're careful/lucky. Loosen the passenger side bearing cap (just a few turns) and remove the retaining clip. You can now fit a skinny punch in there to CAREFULLY spin the adjuster clockwise. Spin one notch at a time, snug up the bearing cap, check carrier preload, repeat if necessary. This may be a stupid idea, but it worked for me. I think in most cases, it's safer to tighten the passenger side than driver as this pushes the carrier and ring gear away from the pinion so if you go too far, at least you won't overheat and destroy everything.
5. Carrier to ring gear and pinion. - Lots of write ups on this. If your pinion depth is good (has no effect on clunk anyway) then you should be looking at back lash. Throw t-case in neutral and give the DS a spin back and forth, watching for ring gear engagement. If you can SEE play, your carrier is too far to the left. Loosen off both bearing caps, loosen the passenger side adjuster a notch and tighten the drivers side a notch. Tighten back up and repeat.
6. Pinion to pinion bearings. - Same deal. if you spin your DS and your pinion has any play whatsoever, you probably have bad pinion bearings. Also give the DS a shake up and down. The pinion shouldn't move at al.
7. If equipped, LSD clutch operation. - The LSD will make a horrible "sounds like gears tearing themselves apart" sound if you dont have enough friction modifier or you have bad oil. With one tire on ground and one in the air, t-case in neutral, you should be able to overpower the LSD by hand by spinning the wheel. If it binds, your LSD either doesn't have oil or doesn't have sufficient friction modifier. If your diff has been sitting dry for a few minutes, you may need to really reef on the wheel to move some oil around and into the LSD clutch plates. From there, it should spin pretty easily. once this has been checked, lift up the other wheel and give any wheel a spin. Both should spin the same direction.

Does this pretty much cover all possibilities, or am I missing something obvious?
Oh yea, check outer wheel bearings. Durp. Lift each side up and give the wheel a lift and shake side to side. Shouldn't budge.

You got that thing fixed yet?

WB9YZU said:

You got that thing fixed yet?

Click to expand...

Seems like it.
Throttle hits the pavement way faster now. There's definitely still a little bit of play but I'm pretty sure that's the worn axle splines or side gear spines. Will give it a bit more of a test drive and wheel it a bit to see if it all holds up, and if it does, I'll just throw some new spiders in.
The LSD is a little grabby, but it's definitely working now and I'm pretty sure it wasn't before. Couldn't slide out of a corner at all before and now it'll leave two lines on light throttle.
Could use a little (more) friction modifier for sure

There's also still some play in the driveline between the t-case and the flywheel, but I'll have it apart soonish to install a new clutch anyway.


My guess is the previous owner didn't bother setting carrier preload. The RE lift he'd installed was mostly hand tight at best and all the suspension mounts were lobed out bad. Seems like everything he touched was super shoddily done, and given the gears look almost new, I'm guessing he installed the gears himself and just forgot to tighten anything