Don't know any mechanics in California, but it should not be too hard to figure out. Please describe the circumstances when the noise occurs. All the time? Only under load? Only when turning? Varies with speed? Once per wheel revolution, or more rapid than that? Drain the differential gear oil into a shallow pan and describe what you find. Fair chance there will be some gear fragments.
Finding a mechanic who knows how to correctly install a ring gear and pinion could be a challenge.
Good luck.