Can't see it, but there is light leaking underneath the pinion yoke on this rebuilt rear end. Could it be b/c the pinion yoke is resting on the wooden dolly? About half the weight is on the pinion yoke in this pic, and the other half is on the rear under the rear cover. I moved the rear end back and rested it on the outer shock mount areas for now to see if it still leaks. They had it that way at the garage also for a bit, although they had some weight offloaded b/c it was also on 2 axle stands.

So my question is... would having it sitting in the pic like below cause the outer pinion seal to leak?

 

NO,it should not leak like that.As long as the pinion bearings have preload,and there is no play or slop there,then the pinion can't move up & down,or away from the seal.I ship all of my rears with the fluid in them,and this is one of those reasons.I want to make sure they don't leak.Yes,there is a chance that the pinion seal is defective,or doesn't have a good enough grip on the yoke journal.I've had a few seals that were defective,and when I dumped the oil in,in started coming out the pinion.Even the smallest tear can do it,or the surface on the outer metal shell of the seal,and the journal of the pumpkin. I take a small amount of rtv silicone & smear it around the outside of the seal before I press it in,then smear/wipe the excces off once it is in.Another thing you could look at is the journal of the yoke,where it makes contact with the seal.Check for a wear groove,or a bad surface.Either one of those can cause the oil to slip by as well.