I just had to tear down the rear axle in my Jeep XJ. Chrysler 8.25. The right rear wheel bearing got noisy, I could only hear it above 55 mph, though. The seal started slinging fluid a short time later.
The issue I have, is that I re-geared this axle about two years ago...or roughly 11,000 miles. I used a master rebuild kit, 4.56 gears (both from Motive Gear),installed a Lokka locker, and new brake shoes, hardware, and resurfaced my drums.
I did install new axle bearings and seals, I don't know what brand they are though (I am going to try to look through my records and see if I can find that info). I changed the gear oil after 500 miles of use, it was clean, no signs of metal.
I ordered new Timken axle bearings (which are stamped with Koyo and USA on the outer race). The bearing that failed has no markings at all on it. I am replacing all of the other bearings (the other wheel bearing, carrier bearings, and pinion bearings) due to the amount of metal that was in the housing from the failed right rear bearing. No signs of damage to any other bearings, or the ring and pinion, but better safe than sorry. I have a couple theories on what may have happened. My leading thought is that the wheel bearing itself may have been a poor quality part. I do wonder if the rear locker, and it's tendency to harshly unlock at times, may be a contributing factor (Excessive shock loads?).
Lack of lubrication is out, axle was full to the filling port, and no heat discoloration on the failed bearing. The pictures show the heavily spalled area that doesn't quite go half way around the outer race, I don't know exactly where that section was oriented in the housing, couldn't see any damage when the rollers and cage were still in it. I assume it had to be either at the top or bottom, because the play in the axle shaft was up/down, not very much side to side.
Does any body have any thoughts on this? Attached File
Attached File
Attached File
Attached File

Gotta make some left turns once in a while.  

Guessing it just could be a bearing that was on the low end of tolerances, maybe the race had some bad metallurgy, or was just junk.  Sure, lockers could increase shock load when they're locking or unlocking, maybe the amount of right or left hand turns you normally make has something to do with it.

What's the bearing surface of the axle look like?

In before someone says because it is a jeep?  Crap, I just said it!!

Probably a bad bearing to begin with I would guess.  I can't even see a cheap Chinese bearing failing that quick...

I did think about left and right hand turns, looked over my normal routes, pretty even for the most part. The axle bearing surface looks the same as the driver's side, undamaged (forgot to mention the axle shafts are Yukon shaft that were installed at the same time as everything else. The only original component in the housing is the carrier.

The funny thing is I just got a rear disc brake conversion kit about two weeks before this happened, so I was going to have to pull the shafts anyway...sucks that I have to do more work now. Damn Jeep. I love this Jeep, but she can be a complete bitch sometimes

I've always had a love/hate relationship with our Jeeps.  We've had 5, and the 94 ZJ was the easiest thing to work on.

Cheap no-name bearings, and you can't figure out why it failed?

Really?

Might have just been a soft/bad bearing.

Also make sure your axle is straight.

How much off roading do you do?

going with this or it was just a bad one. Sucks though.

I installed a u joint on my s10 years ago after the oem one went bad at 35k miles. Oem one wasnt drilled across the one direction and it dried up. Bad from New. Installed a new USA made one with a zerk and installed it. It lasted maybe 5k and was smoked. Put in another, different brand, and it lasted 100k miles atleast until I sold it.

Not the case, I do make a point to buy OEM quality. I also strive to make sure my work is properly done. I wouldn't have purchased shit chicom wheel bearings. Though maybe I got took by the seller. The metal does look like piss compared to the new ones I have in hand.

last time I had it on the alignment rack, it was good, tire wear also indicates no bad toe or camber issues.

Two or three decent overnight trail rides a year, random beatings on the farm, and I do like to hammer down stop light to stop light. Trailer towing, too, but never over about 3K lbs.

You've been china'd.

more than once I got a different part in the box than what I was trying to buy.
it would have "worked" but it wasn't what was marked on the box.
one time they pulled a used part out of the box when I was buying something.

so it isn't beyond the realm of possibility that someone swapped the cheaper one with a more expensive one in the box and paid for the cheaper box.
when buying 2 of the same thing if they don't match, I make them get another till we figure out which one of these things is not like the other.

I am all for buying at rock auto or amazon, but if it is a part with a lifetime warranty like Timken usually has, I am buying local so I can see the part.