[ford38v8]

Hary, As this condition is not a new issue, I wouldn't get excited about it before determining what the cause is, and the extent of repair it will likely require.
In the order of need, the first thing to do is to remove the wheels and drums to inspect the brakes. If oil has migrated out to that point, the problem becomes urgent and must be fixed immediately. If the brakes have not been saturated with oil, you can celebrate and proceed slowly to determine the cause of the leak.

Your transmission leaks as well as your differential, which tells me that there may be an excess of oil in both systems, or that the oil used may be too thin, The two systems being connected by the torque tube, oil is relatively free to migrate from one to the other, so one leak may reflect an overfilling of the other.

On both the transmission and the differential, the correct method of filling is from the side plug, to prevent overfilling. With the car level, remove and replace both side plugs one at a time to confirm that one or the other is not presently overfilled. If it is, oil will drain out, which will be another cause for celebration.

Now determine the oil used when those systems are serviced. If motor oil has been used in the past, that is way too thin, and will quickly damage both units as well as leak out at every possible point. A quick fix in this case will slow the leakage and prevent further damage, simply by draining both and filling with the proper weight oil. If neither the transmission nor the differential are noisy now, you're ok to proceed to find and repair the leaks.

As advised above, clean the units, and watch for the location of the first oil to escape, then decide if a repair is worth the effort. Remember the sage advice about Fords: "If it don't leak, it aint got no oil in it".