Marine Trader Europa - Lehman w Paragon Transmission

[gdinsdale2017]

I am looking at a 1976 Marine Trader Europa with a Lehman 120 with 4k hrs - The owner says the transmission - Paragon model ?? has a leak. Any suggestion on repair or replacement?. 4k hours is not a lot for a boat this age I wondering why the transmission has a leak ?

Any help appreciated

George