Bongo Fury

I've been cheerfully overlooking a leaky front differential oil seal for some time as I have had no luck finding the replacement part.

It's the seal where the prop shaft goes in. (not the drive shafts)

How about oil seal swell additive, such as "Wynn's Engine Stop Leak" is it worth a try?

The PN for seal is
M05327165
These can be obtained from Mazda / Motor factors If not with this PN cross reference.
It would be advisable to check for lift on the pinion before you think of a seal replacement or stop leak.

Good Luck.

also check the breather on top of the diff is not rusted closed, if it is its just trying to breathe when hot so making a leak that isnt really there.