Very very little leaks out of the axles. I guess you could say the wires are possibly a bit wet and that's it That may be from before though. As long as you only have enough oil in the hub to fill it say to about a third- so the oil level is well below the axle, you shouldn't have any dramas. Having a little vent hole is an absolute must. I tried it without and within a minute of testing, oil started to seep out of the axle, following the air as it expanded inside and escaped.
When I replace the stator in this motor, I'll seal the axle properly from the inside and then refill it with oil. Then we shall see how much power these little MAC motors can handle...
Or then again maybe not- don't want to kill the clutch! I also have a 9C 8x8 which is going to get oil cooling and push lots of power through it. The plan for the mac is eventually to go in a custom frame as a mid drive.
I drilled a small hole (1mm ish) near the axle. I drilled from outside to inside, with the drill angled so that the hole goes from the axis towards the circumference. My logic was that when spinning, any oil that comes near the vent hole will be flung back inside the hub...seems to be working so far.
I'll try and chuck a couple of photos up- not terribly exciting though as it's a sealed hub! I did try a filtered air cooling system but that did nothing so the holes are blanked up with plastic bungs glued in. One of the bungs has a hole and rubber stopper for filling the hub with oil.