Three problems related to power train driveline have been reported for the 1999 Ford Explorer. The most recently reported issues are listed below.
Front end differential bearings freezing up.
Drive train-high pitched squeal/whistle noise from front end at speeds 20mph to 55mph. Four attemps by the Ford agency have been made but the noise still remains. There have been a total of 14 reports made to NHTSA for 1998 & 1999 for the same problem as I interpret some of the web site reports. No safety defec tlisted in summary.
The driveline of the vehicle vibrated at 60-70 mph, consumer put on 15" wheels and new tires which stopped some of the vibration, the consumer believes some of the vibration was caused by the tires and some is caused by the driveline (firestone wilderness ap p-255-70r-16). Nlm.