Just curious do all of the failed front diffs. have the off-road package with the 4:1 T-Case?
This is starting to look like a housing flex problem. What happens is that the differential gear teeth are tapered and they try to spread the diff. case apart when subjected to a high torque load. When the case spreads the teeth are no longer in proper mesh at that point (the teeth make a high flank contact similar to being setup with excessive backlash). A high flank contact severly loads the tooth on the ring gear and causes it to break away from the base of the ring gear. The measured .022" backlash would be indicative of a housing that was severly loaded enough to stretch the housing beyond it's elastic limit. The housing was sprung and never returned to it's original shape ( similar to overspreading a Dana housing too far when installing a gearset. A housing can be easily ruined if somebody gets carried away with the case spreader as they should never be spread more than a few thousands of an inch to facilitate getting the carrier and bearings back into the housing).
BTW- the tech that actually took time to do "failure analysis" and measure the backlash before removing the gearset is a pretty good tech. Most would never have bothered to take the time to check.
