Due to the drag from the transfer case clutch, the front driveline components are spinning most of the time anyway; they’re just not engaged to the wheels. On non-Raptor F-150 and Expedition, the TSB for capping off the system didn’t reduce fuel economy enough to change the ratings. However, it may have on Raptor, which is possibly why it’s excluded from the TSB.FTO....so whats your thoughts on capping the system though? Seems with the CV's spinning full time efficiency goes way down, and mileage too..