Problems Putting in the selector shaft seal

I looked at my transmission.
Does the 904 torquflite have this pivot pin o ring. I don't see a place for it.

The transmission is out of a 76 charger.

It's between the extension housing and the rear of the main section of the case and is partially hidden when the extension housing is on.
FYI, there is also a cork gasket under a plate where the trans mount bolts to the trans.

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