Rear Block Babbitt

[2935ford]

Well further info to share and have some insight.
The picture shows the block rear main and inside the red you will notice an elongated dark spot. That spot is a hole clean through the babbitt. Is this the source of my rear leak?
We sprayed brake cleaner into the hole and used air to see where or if it exited. We could not determine that but air from the underside of the rear main made fluid come out of the hole.
I'm pretty sure there should not be holes in the babbitt. What can be done about filling it in?