I have had My 2015 Lariat FX4 SC 3.5 Eco with a FabTech 4” Lift for a little over a month, over the last few weeks I have heard and felt a vibration coming from the front end. After looking through the forums I believe it is the IWE. I cycled the system and the vibration stopped. When it happened again, I went down to My local Ford Dealership and they told me I needed to take it to Les Schwab to have it looked at, because they thought it was related to the lift. I took it to Les Schwab and they told me that the lift was not causing the problem, but the alignment was off. Les Schwab corrected the alignment and said that a cv boot was torn and I should have it replaced. I went back to the Dealership, informed them on what I was told and made an appointment to have the IWE looked at and the cv boot replaced. I told the Dealership that they can have My Truck for a week, as I was going to be out of town. The Service Department did nothing to fix any issue while it was there. They claimed that they did not hear the vibration (ok it comes and goes, I understand that) but they didn't even replace the cv boot. In fact, they also put in the service notes that the rear differential was seeping fluid. Seriously, you have my truck for a week and you can’t fix a seeping rear differential. Needless to say I went back today and spoke with My Salesman and the Finance Manager. They told me that they will get back to me this next week so we will see what happens next.