Transmission gurus, please comment, Wear on bearing retainer plate Options

[MrKona]

I'm nearing the final stages of a "partial" transmission rebuild. To make a long story short. I started off with my original and a donor tranny. Turns out the donor had a broken shift fork, but no other problems that I can see, all synchros and gears look alright, case bearing races fine. No reason to take the shafts apart, so I'm reinstalling the drive and pinion shafts into a freshly cleaned case with all new gaskets and seals, and a brand new pinion shaft intermediate plate bearing (The old one fell apart in my hand, sound familiar?). I'll use the shift fork from the original transmission.

My concern is wear that I spotted on the bearing retainer plate that mounts on the intermediate plate. First gear had worn a groove in the plate, just less than a mm at its deepest. There was no more metal-on-metal contact, as first gear appears to have completed it's job of clearing away metal. I couldn't see any wear on first gear, tells you how tough these gears are. (As I can tell from the blue goo gasket sealer, this transmission looks to have been part at least once before).

Anyone have any ideas what could have caused this... where the tolerances could be off? It's going to nag at me as I'm putting this thing back together. Thanks.

By the way, I had the outer case plastic bead blasted and it looks absolutely beautiful. When it's done, I've got to post some before and after pics. I can't believe the difference!