One problem related to differential unit has been reported for the 2006 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Toyota Highlander based on all problems reported for the 2006 Highlander.
2006 Highlander generates roaring type noise heard from the front end while driving at highway speeds and humming noise heard after 40mph. Toyota service dealer found that front differential is bad. Estimate $4,500 to repair.