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First a (maybe silly) question: Have you filled oil up to the correct level? There is a hexagon screw in the front end of the r.h. side of the gearbox, -an oil level plug. Before filling with oil, you unscrew this plug. If oil is running out, you have filled too much. Else refill until oil comes out of the hole, and let it run until no more is coming out. Then refit the plug. I had an oil leak from the gearbox on my ’36 flyer, and discovered that the oil level was too high. With the correct level – no more leak! You also need to use a sufficiently heavy oil. A SAE140 straight (no hypo├»d) gear oil (Shell Dentax) is OK. It has a “body” similar to a SAE 50 monograde engine oil. If the oil is too thin, it will splash about a lot more than a heavy oil. Personally I use Castrol R40, which may sound a bit exotic, but it adheres beautifully to all internal surfaces in the gearbox.

If this does not help, it is possible to fit a modern oil seal. I have had that done on my ’38 flyer in connection with a recent gearbox and clutch overhaul. I am certain that Roger Moss, who helped me, can steer you in the right direction.

Kind regards,