If there is a vibration or noise at highway speed, it could be from the frontdrive shaft and may require replacement of the double cardan joint. A double cardan joint is a type of driveshaft joint that uses two universal joints.
Car Problem Reports
Ford F-150 Vibration or Noise at Highway Speed
Ford F-150 Problem
Drive Trains Affected: 4WD, Automatic Transmission
Average Mileage: 137,610 mi (20,050 mi - 189,000 mi)