Differential gone

Is it practical to rebuild a front differential? My transmisson was rebuilt thirty thousand miles ago but now the differential is gone. ('92 with 130,000 miles).

In calling around the only option seems to be a complete transmission rebuild. Is that the best way to go? It always shifted fine but suddenly started making a grinding noise from the front, and on the way to the repair shop the next day it made a loud bang clunk clunk clunk. It was towed the final 1/4 mile to the shop. My local guy isn't a tranny expert.

How huge of a repair bill am I looking at?

To fix or part out that is the question.

Thanks,
Rock