NP205 Driven gear

[TJ805]

What seals this from the inside? Rubber o-rings? Flat nylon? Pressure fit? It appears to have place for seal, but mine has none. The search window, as usual produced nothing, so I'm asking anyone who might know.
-Thanks

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[SquareRoot]

O ring. Do you have the external piece that contains that O-ring? Seems they've become impossible to locate.

 

[TJ805]

I have the screw in "retainer" part and the gear. Unfortunately my pics won't download, so I used a web pic. The "screw in part" threads into the tranny over the gear shaft, and the speedo table threads onto it. Does the o-ring go over the shaft after the screw in part goes on, or does the screw in part screw down over the o-ring? There is no apparent place for the o-ring inside of the screw in part. The gear shaft has what looks like a groove where it seats against the screw in part.