Differential Unit problems of the 2013 Subaru Crosstrek

At approximately 64k miles our xv Crosstrek began emitting a loud hum from the rear and our gas mileage decreased significantly (18 mpg). When we took it into our mechanic, he found that the rear hubs were dangerously degraded and that the rear differential was failing. In his opinion, failure of those systems at only 64k miles suggested a design or part defect.