915/68 74E vs 74F - w/Pics

[dentist90]

Surprises just keep coming with this project. I posted previously how I found a crack in my diff housing necessitating it's repair or replacement. I got a replacement housing from a Vancouver Porsche dealership who could not give me any info as to they came to posess it. I noticed the casting part #s were slightly different (7R vs 9R as last digits). I also noticed the trans model # is different, 74F vs 74E. My Bentley doesn't list a 74F so I don't know what it came from but it's non-oil cooler.



I am preparing to swap my old diff (complete with ring gear and bearings) into the new case. I had just removed the old output race from the case when I noticed that the bores are different for the mainshaft, 60mm for my old case vs 55mm for the replacement. See photos:





I had heard of a smaller diameter bearing for the turbo but Pelican lists the turbo and non-turbo input shaft roller bearing as the same part (999-110-146-00).

Q: What case have I got now and where can I find the appropriate sized bearing. I like the idea of the thicker webbing between the two bores as my old case cracked right there.