here is the story:

for last couple weeks I have squeaking somewhere in the rear, last weekend something started to rattle, not when I was pushing gas pedal but when I let it loose, not during accelaration but rather on idle/slowing down/ run,

I checked suspension, linkages, trackbar, wheels - nothing, all looks ok,

my suspicion were axle shafts, maybe bend, maybe flange bent, with 37" tires I expect that some day stock axles will go, so two days ago I ordered new axle shafts from Northridge, should be here tomorrow,

tonight I said "lets prep JK for new axles", and started working,
removed tires, breakes, rotors, and I was on to empty diff from fluid,
I removed plug .... and this is what I found


plug full of metal pieces, fluid was silver ... I said "$$$$ not good"


some pieces of metal were 3/8" long, sharp

so next I removed diff cover ... and here ya go





teethes of gear cracked along inside side of the gear, pinion gear looks intact (will check tomorrow) ... my last trails were in Moab, long time ago and I made it home, no wheeling recently ... street driving ... "nice driveway" ...

those are 5.38 gears, with about 10K on it

so, it looks that I am ahead of busy weekend with cleaning and rebuilding my rear axle,
I guess all bearings are gone, pieces of metal were all over inside diff housing,

I have two questons:

what you think about that weird way teethes are broken?
for me it looks like low quality piece of metal used for manufacturing the gear,

and,

what do you recommend regarding fixing this? any advises before I will go further?
I suspect my differential is gone to, should I replace with stock or anything 'harder'?

I think about this more like opportunity than problem ... let me know.

 

will try, gears were done by local shop and they ordered gears,
but truly said I do not want to deal with that brand anymore,

now it is about building something strong and reliable

 

I'm starting to think it was the install and not the gears. What gear company was it?

 

what makes you think it was install?

 

I'm curious as to what gear company as well. I'm about to install a new set this coming up week.

 

Gear installs are pretty tricky and even reputable shops have a bad install occasionally. And unless the gears see severe abuse on the trail (wheel spin, etc...) then they usually don't fail with normal driving. More often than not, gear failures are caused by improper setup rather than poor structural integrity of the gear itself.

 

It could also be that one tooth fractured, the chipped metal fell to the other teeth, and caused the others to fail.

Then again 5.38 gears have a lot less surface material so fracturing isn't totally ruled out, especially running 37s.

Maybe there was a defect in the gear.

Maybe there was a defect in the install.

Just get a new gearset in there. It's bound to happen.

 

Just had 5.13's installed in my 08 JK and didn't get 50 miles on them before it started to rattle hard when the gas was applied. Took it back to the shop and the backlash had opened up to 40/1000th. We shimmed it, but another 50 miles and we are back where we started. The guy at the shop said that this might just be a "soft" set of gears and so we are replacing them again next week.

I tend to believe the guy at the shop. If the gears were set up wrong the first time, could only 50 miles effect them in such a way as to not be able to hold a certain position when they were set up correctly? I dunno. All I know is that I would change brands if I could, but I don't know what would happen it I ran brand "X" in the front and brand "Y" in the back.

This has been a real pain for me. Hope yours goes better.

 

All the serious wheelers here swear by Superior Gears. My jeep mechanic has installed them for years and that's all he'll install. I'll be putting some 4:88's in this summer. He indeed told me if your off at all with shimming shit will go wrong.

Sorry to hear about the mishap but Grab some Superior's from Northridge

 

UPDATE

working on the rear axle:
- I measured backlash - 15/1000th - probably to big (is it the reason why it broke?)
- pattern: came out ok,
- I removed 'pumpkin', put it apart into pieces - no damage, looks ok, will clean and put it back together (good news, I was afraid that it is damaged to);
- e-locker looks ok either; locker plunger looks ok to but need to clean it;
- during removing parts from diff case I continue to find pieces of metal from broken teethes.

I am still not sure what cause the damage (bigger than required backlash?).

Here are the pictures of whole ring gear:





My plan now is:
- order new gears (Superior),
- order all new bearings kit,
- clean thoroughly entire diff case to remove any metal pieces, and
... rebuild rear axle.

My neighbor has all the tools (case spreader, etc.), I know it could take couple times before I will get right pattern but I want to learn it. I feel confident doing that.

The axle shafts (Superior) are already in my garage with bearings pressed and ABS ring installed (nice work Northridge4x4!).

what else I could to my rear axle to make it strong?