The customer has a loud growling sound coming from the rear differential what parts are covered?

Driveline coverage includes lubricated parts contained within the differential housing, transfer case or transmission case. It does not cover: differential housing, transfer case, transmission case, axle (s), pre-packed axle bearing(s), CV joint(s), CV boots(s), driveshaft(s), case flywheel, clutch plate, pressure plate unless damaged due to a failure of a covered part.