IWE Solenoid?

The Integrated Wheel End (IWE) system in the 2018 Ford F-150 is responsible for engaging and disengaging the front wheel hubs to allow for 2-wheel drive or 4-wheel drive operation. The IWE solenoid plays a crucial role in controlling the vacuum that engages and disengages the front wheel hubs.

If you suspect an issue with the IWE solenoid in your 2018 Ford F-150, it could result in problems with the engagement or disengagement of the front wheel hubs. Some signs of a faulty IWE solenoid include:

Grinding or clicking noise: You may hear grinding or clicking sounds from the front wheels when driving, especially during acceleration or deceleration. This noise occurs when the IWE system fails to properly engage or disengage the front wheel hubs.

Front wheel drive engagement issues: The front wheels may not engage when switching to 4-wheel drive mode, resulting in a lack of power transfer to the front wheels.

Vacuum-related issues: The IWE solenoid uses vacuum to engage or disengage the front wheel hubs. If there is a problem with the solenoid, it can cause vacuum-related issues, leading to improper hub engagement or disengagement.

It sounds like the check valve in the IWE solenoid is not working. I would swap it out for a new one which should fix it. Check out the images (below). Please let us know what happens.

There is a bulletin Ford put out for the solenoids. It has you change a one-way check valve, solenoid, and verify vacuum lines. If it has 4 Auto, Ford actually has you bypass all of it, run them locked (something about the higher end system being able to split torque better, so it's doesn't cause the normal drivetrain binding when locked).