Hey. I have a 2017 f-150 lariat 3.5 ecoboost with a front left noise. I’ve replaced the brakes (rotors and pads). Mechanic at a shop tells me it’s rear diff making noise although noise is front left, maybe front diff?. Please see video. Any help would be great. Speed doesn’t really effect the noise, anything over 5mpg it does it. Not sure what this noise is but I’m sure it’s familiar to someone out there!

 

I played the video at a very slow speed and sounds like a picket fence noise and the pitch is not like an internal differential fault would sound.
Something on the outside is rubbing such as a bent backing plate.
If the noise is only when the vehicle is moving, maybe an IWE if you have 4wd.
When the engine is running, vacuum is supposed to disconnect the IWE. If it does not and they touch, you will hear and may even feel it.
Jack the front up both wheels off the ground, start the engine in park and turn each wheel by hand. If it is something is amiss you should feel and hear it.
Good luck.

 

It sounds like IWE to me. Lariat, put it in 4A and drive it around, report back.

 

My thought as well.

 

I still hear the noise in 4wd. Could it still be the IWE. Next step for me would be to replace the hub (iwe) assembly?

 

IMO, likely not IWE if sound stays the same in 4A. Does the sound go away when you turn left or right? Play in a parking lot... Certainly could be a wheel bearing.