The crack was between the bores of the old final drive housing, through and through. The pinion bearing race was indeed loose (very loose) and the pinion bore pummeled.
The new case is in much better shape. The pinion race in that one was still in and I had to tap it out, although it didn't take much effort. I'll use some loctite race and bearing restorer when i put the new bearing in. The race that came out of my old case (goes with the pinion shaft) is a snug fit in the new case, but not quite an interference fit.
I do have the matching pinion and ring gears. I plan to swap ALL the internals from one case to the other. More like I plan to swap the diff case out on my original tranny. The only reason I opened it up was to repair 1st and 2nd synchros. Not too happy to find the cracked case. I had no symptoms, such as gear whine on load or overrun, to indicate something was going out of alignment.
I think that part # you gave me is the same one I got from WEVO, but Pelican describes it as the pinion bearing. I'll look into that. It's definitely the 55mm (outer) one I need.
If the case that came from my car was from an 83 or older someone re-stamped the bottom with 74E. My Bentley manual doesn't have a description for 74F... jumps from 74E to 74G, which would also be stamped 915/73. I'm guessing the new one came from a late 84 or early 85... doesn't matter as long as I can get the updated bearing
OK: How do I get the old one off?