I knew first and second gear syncros were in bad shape. Third is not bad, reverse has some issues.

First problem no gaskets, it is sealed with rtv, I have know idea what the preload and backlash for the ring and pinion is at his point. I guess I need to check the both.

Next I notice the the reverse idler gear thrust washer is badly scored and worn.
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Thinking to myself I think we are missing a part. Bearings are just extra parts, you don't need those. /s

The reverse idler gear does not look badly worn from the thrust washer.

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However the teeth look pretty beat-up.

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I think I might need to find a replacement reverse idler gear. I think without the bearing between the reverse idler gear and thrust washer, it was sometime touching the first / reverse shift sleeve.

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Some syncro rings have the expected wear, but this one has groove in it. it seems to be a manufacturing defect.

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Some of the brake bands show wear, i'm not sure if that is normal. Some of my syncro hubs look more like igloos than peaked roofs.

Yep, ugly for sure.

Pinion will be marked - procedure to set is in factory manual but requires some special purpose tools to measure and set the ring and pinion properly.

The main issue a this point will be that it was running for while without the proper pinion setting (due to the RTV) and the wear patterns on ring and pinion are now established. Setting it yet again back to OEM position will probably result in even more noise and accelerated wear.

Given the other issues you have I'd probably just find a new transmission.

I think it ran for far under a thousand miles set up this way. It was an engineering project and sat for decades. I did not hear any bearing or ring and pinion noise. I should have tools to set up a ring and pinion, it has over 30 years since last set one up. So I'm a bit rusty.

My plan is the check the bearing preload, back lash, and the ring and pinion contact pattern, that should show me how much it has worn.

Finding the a good used replacement thrust washer wasn't to bad. I had to email around to find a good reverse idler gear. Porsche still makes the bearing.

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Some good news on gaskets, the sets have three gasket thicknesses again.

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Since mine was rebuilt with RTV and I did not have and ring and pinion noise. I am going to try it with the thinest one.

Since I don't have the tool to measure the pinion depth, I am attempting to check the gear patterns. I'm having no luck finding gearing marking compound or Prussia blue locally. I ordered gear marking compound what is delayed a week. I tried white lithium grease. It seems to be even across the whole tooth. Maybe that is normal and gears with a 100k on them.
I was able to measure backlash, well enough to have some comfort level, that is still in spec.

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