Iggy,
It seems to that the lock was improperly installed. Therefore the side adjuster backed off, causing the ring gear to develop excessive backlash (which would cause noise when taking your foot off the gas), and the ring gear moved over enough to break off the improperly installed lock.
I would remove the ring gear and carrier, wash out the banjo with a full can of brake cleaner, blow out with air. Clean the ring gear, bearings, races with brake cleaner and air. Re-install everything and previously described and you should be good. Don't forget a new cover gasket. I prefer a gasket, but a bead of silicone works too.
I wouldn't recommend using a power washer as someone posted, the water can be impossible to get out of the axle tubes, and you will contaminate your new gear oil and get milky.
You can try to get Dodge to make the repair, you have a good case, but it might be easier to fix it yourself than deal with that hassle.
While your at it this is a good time to install a limited slip differential :^)
Tony