Cable-shift Torqueflite - ’64 vs ’65

There's a seal between the output shaft and the inside of the yoke; spline count and pitch are the same, but there's no groove/missing spline; and there's a small hole in the tail end for a pressure relief. I've been told (or read, maybe) that the newer ones don't seal up correctly, but with the o.d. being the same (which I'm pretty sure it is) and the extension housing seal the same, I'm not seeing why that would be the case.

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