C20 Dana 60 Wheel Bearing Grease or Gear Oil?

[Big Kev-O]

When I was rebuilding my drum brakes on my Dana 60 Axle I found lots of greasy crud all over underneath the drum. I figured the outer hub seal needed to be replaced so I pulled the hub, replaced the seal, cleaned & greased the bearings and bolted it all back up. When I was sliding the axle (full float) back in I realized there is no axle seal to keep the gear oil inside the axle tubes. After a few Google search I read that floating Dana 60s do not have axle shaft seals, the bearings do not get greased and the gear oil lubricates the bearings.

Do the bearings get greased or lubed by the gear oil? The gear oil thing seams kind of strange to me because if the truck is traveling on a flat surface for an extended distance how is oil supposed to migrate all the way down the axle tube to keep the bearing lubed?