Saw this on PTS: May 13 2015 6462-2011-2015 F-Super Duty Equipped With Electronic Shift 4WD- New Hub Seal Kit Available Some 2011-2015 F-Super Duty vehicles equipped with electronic shift 4WD may require axle seal (3254) replacement due to vacuum leaks. The axle seal part numberhas been updated to simplify part ordering. Follow normal diagnostic proceduresin the Workshop Manual (WSM). Refer to WSM, Section 308-07. If axle seal or seals require service, order (1) axle seal kit 5C3Z-3254-B per side, as needed. Seal, hub gasket, hub o-rings and hub screws are now all packaged with the axle seal. For Dual Rear Wheel (DRW) vehicles, (1) package of wheel extension nuts W520506-S309 is also required. Use applicable labor times found in SLTS Section 3 foraxle seal removal and installation and Section 7 for 4WD diagnosis.