If it is gear oil, the seal is way down the tube by the center section where the gears are...a little outboard of the center but not much.
If its grease, it could be the hub seal for the bearing...the knuckle is sealed by the spindle from the drum area...if you see leakage around the spindle mount, then the knuckle...harder to leak that way I would think.
Did you put grease on the backing plates to prevent squealing/chirping the lat time they were assembled? Did you maybe use a lot and it got all over the shoes?
Wild off the wall guess there...
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!