[Rich-Tripower]

The seals actually look ok when taken out other than dings inflicted in the removal process. The bore in the housing is smooth all around. Yoke is now almost new so also new/smooth. Pinion turns concentric to the housing hole. All bearings were new, diff professionally built. We haven't used sealer on the bore as the seals come with sealer already applied. Instructions say more sealer not needed. Buy maybe a film of RTV would help? Maybe pull the vent and apply compressed air to see if anything comes out the seal to see if vent is getting air to the pumpkin? Grasping at straws.

Maybe seals pressed in too deep or too shallow? This has been a problem on Chevy 12 bolts for years since most have stopped making the right seal and the ones listed as correct don't fit right. But even those don't leak like this.