Some 2015-2018 F-150/Expedition/Navigator vehicles equipped with a 3.5L/2.7L EcoBoost engine and four-wheel drive (4WD) may exhibit an intermittent grinding type noise while driving in two-wheel drive (2WD), most commonly on acceleration. This noise could appear to be turbocharger related. After engineering analysis of returned turbochargers that have been replaced for this condition, no concerns were identified with the turbochargers. The grinding type noise may be related to the 4WD system integrated wheel ends (IWE). To aid in diagnosis, shift the vehicle to 4WD and attempt to verify the condition. If the grinding noise no longer occurs with the vehicle in 4WD a IWE vacuum system and/or mechanical fault may be present.
