spinlock

Some things to consider:

If the install is just marginal then improper break-in might have also contributed.

Did you buy the Jeep with the gears in it?

You are also running a tall lift. Are the driveshafts and pinion angle stock?

BTW, it's not out of the question to have the diff fail before the axles even if gearing was properly done.

Also, I can imagine your blood pressure level given the circumstances, so it's great to see you have the backbone not blast the installer without a bit of investigation first.

No1AP

Ok, been a while but... here goes.
Something I learned, that everyone else probably knew...
On the D30 front, when you are reinstalling the carrier, and you go to put the shims in, I was led to believe that the shims went on the outside, outer bearing race between the bearing race and case. There are kits out there that use this method, also the method I would recommend due to ease of install. But the original design was for the shims to go between the carrier and INNER bearing race.... ooooohhhhh... I felt pretty retarded when this was explained to me... needless to say. This makes the whole install process VERY long if you have many corrections to do because you are constantly pressing on and removing bearings. A good technique is to grind out the old bearing to slide on and off easily, but I was worried about inconsistencies in manufacturers...
Anyways, I think the whole reason it broke in the first place goes back to the whole idea of engineering something that is going to break, where you want it to break... for example, having such a tiny toothed ring gear on such a small diameter and as much punishment as I dealt out, it was just a matter of time before it gave. Same gear ratio on a larger diameter ring, different story due to larger, stronger teeth.
If none of this makes sense, I am sorry. Long day, really tired. Hope this helps someone...
Josh