Here is a Pinion Seal Delete Kit for 2.5 Ton Rockwells, by cutting off the shaft and welding in this plate, you eliminate a potential spot for leakage on a 2.5 Ton Rockwell.
The Pinion Nut only holds the yoke on, the bearing retainers hold the bearings together. You can delete the extra yoke and Pinion Seal to make one less spot for oil to leak out of, or water to get into. The Pinion Seal Delete Kit doesn't affect anything functionally.