I have a 2014 EL limited with the 5.4. I have been through the typical IWE grinding issues. I have replaced the following: Driver front IWE Driver front CV axle Front diff. 4x4 solenoid Check valve Each of these fixes cause the grinding to disappear for a few days but the grinding always comes back. The grinding is intermittent and lessens or goes away once we have driven for a few miles. I also did as many vacuum tests as I know and nothing seems to be leaking as far as I know. My theory is that the hub assembly is was damaged with all of this trouble shooting or there is a vacuum leak somewhere else. Will replacing the hub assembly help?