It was always a puzzle to me, packing these monster bearings only to come along afterward and find all of the grease had worked it's way out of the bearing surfaces; my millwright friend sent me a bearing I had tagged and replaced aug/94, still [maybe anyway] running in a fan shaft some odd 28 years later in continuous service.
What I often recall when I pack these bearings, and come back and check pillow blocks afterward, is that nearly all of the grease works it's way toward the outer case; my theory goes; these bearings do not rely what so ever on lubricant; they are hardened rollers riding on hardened races, and frankly scarlet, don't give two ____ whether there's a film or not; they are metal to metal, they are not riding on a film of grease, moly or oil; I think the moly [or grease] preserves the metal, and that's all. babit bearings, poured bearings, so on enable a film of cross sectional area which assists in "flotation" of journals, roller bearings do not, wake up... these are hardened compliant surfaces.