Manual Steering Box Rebuild Questions

If everything gets coated on assembly and you pack the box with enough grease, there is nowhere for the grease to go. I've rarely seen an upper sector bearing failure. It's almost always the worm gear assy and in that part, it's usually the contact area against the sector gear or the bearings on either end. Water and/or dirt incursion because of failure of the imput seal is usually the cause of the bearing failure, not lack of lube.