365 selector leak

[HoraceM22]

Hi again
My '74 TCS had a slight leak from the selector shaft so, during my engine rebuild I decided to change the oil seal and what a difference - IT'S A LOT WORSE,!
Does anyone know the sizes of the seal? I know it is 15mm bore.
Has anyone ever fitted a smaller bore seal, say 14mm?
ATB
&

[HoraceM22]

I might add that I refilled the gearbox with modern ""thin" racing transmission oil

[TurboFource]

Not sure that is what you want to use since the ring and pinion gears are lubricated with the same oil.

[BDA]

If you still have the old seal, the size is printed on it and should be available at a good bearing/seal supplier.

I would use a transmission oil with a weight similar to the 90wt recommended (at least I think I remember that was the recommended weight). I use Red Line.

[jbcollier]

The selector shaft runs in a bushing.  If the bushing is worn, a new seal won't last long at all.