This has been a 2 month journey for me and I am at my wits end. I have had my entire IWE system replaced. Actuators, hoses, valve and solenoid, The noise and the engaging of the actuator is at random. There are times I can drive miles with no issue and there are times I cannot accelerate without the noise and the actuators trying to engage. There are times I can barely touch the accelerator and it acts a fool. The more driving throughout the day the more it tends to flare up. Sitting for 4+ hours seems to reset the whole thing.

It seems to show its ugly head to more I have been driving throughout the day.

I have had my truck at this particular dealership off and on for 2 months now. I have explained that it needs more than just a 5-10 minute drive around the block. I have only been able to replicate the sound with a representative one time and after that is when they replaced the actuators. The service department has been a pain to deal with. They don't really seem to care.

MY QUESTION: Is there something else that could be causing this. Manifold issue? Vacuum Reservoir leak?

 

Firstly, year, trim level, engine, could be helpful.

 

2015, SCREW, King Ranch, Ecoboost.

 

OK, I'm assuming the noise is like a can with marbles being shaken? If so, and seeing you have 4A, stick it in 4A and drive it, does the noise go away?

 

Starts out sounding like you’re dragging a piece of tin (inside the cab). Then you can hear what sounds like metal clinging together. While driving and the noise appears I have switched to 4H many times and it goes away for a period of time.

 

Other things that can make similar noises are loose heat shields (check everywhere as there could be some in the engine compartment), something on top of them, the brackets above the catalytic converters if they are loose.

Could also be the front diff or transfer case.

New IWEs have been known to come with to much grease in them that inhibits or slows down the movement of the IWE.

Also could try a different dealer, especially if still under warranty.

 

So you eventually get the noise again regardless of being in 4H/4A?

 

No the noise disappears. I have not driven with 4H engaged more than a couple miles each time. After taking it out of 4H, It will re-appear later. Sometimes it comes back a couple minutes later or can take longer.

The issue is not consistent in rearing it’s head. But like I said more prone the longer it is driven.

 

It appears then, that you're loosing vacuum and the IWEs want to engage. I know you mentioned you changed out the checkvalve, but even new ones have been known to be bad. Your '15 would have come with the older valve. Ford updated it awhile back, the new one is blue and white, the old black and white. If you don't have the new, I'd suggest to either run in 4A, or pull the power to the solenoid. Either way the IWEs will engage and keep them from grinding and destroying themselves.
Here's a link to the updated valve;
Tube Assembly - Ford (FL3Z-3A788-B) | TascaParts.com (1)

 

My bet is a vacuum leak. I just changed a hub and IWE yesterday due to it making noise. Once the new parts were installed I cranked the truck up and the IWE wouldn't disengage, then finally it did. Turns out it was a cracked vacuum line allowing it to get some vacuum but not enough to fully disengage it. Changed the line and all was good.

Wayne