Three problems related to axle assembly have been reported for the 1999 Ford Expedition. The most recently reported issues are listed below.
Rear axel seal leak caused by wear of axel surface at bearing. Vehilce only has 77,000 miles. This required replacement of axel per dealer ($600. ) it was stated by mechanic that this is a common problem to Expeditions. Vehilce has been serviced at or better than mfg specifications. Leaking seals could lead to failure of axel or differential due to loss of lubricant.
Ford 1999 Expedition ; estimated from a Ford dealership service department $1,899. 67 + tax to overhaul rear axle. Loud roaring sound from rear wheels driving approximately 10-15 mph, which sound increases in pitch with faster speeds.
Front drive axle pops and vehicle shakes when turning . Also pops and shakes when accelerating/decelerating. Possibly due to defective spider gear(s).