Stemco 392-9112 Grit Guard Kit. Includes 320-2213 blue seal and 315-1515 Grit Guard Axle Ring. 663 or HM516449 Inner Bearing. 555-5072 / 551-5364 Universal Head / Hub Tool. 570-0023 Bearing Guide. Application: 44,000 Lbs. Drive Axle, Mack.