Hello all, Jim from CT here. I have a 2013 F-150 XLT, 3.7 engine. Few days ago my truck all of a sudden sounded like an airplane. Moaning/grinding noise from front end. At the time i was shifting in and out off 4WD as it had just snowed. Shifted back into 2wd and that's where the noise started. It has been intermittent ever since but makes the noise more often than not. Shifting to 4wd the noise immediately stops. Shift back into 2wd and it acts up again followed by by a loud clunk a minute later. The 4wd is not fully disengaging. I have replaced the 4wd actuator solenoid {near brake cylinder} and also replaced check valve assy. Still no good. Inspected lines going into the hubs, i do not see any holes or tears. What's left to check?

Thread title correction, should read "4WD IWE system"

 

https://www.f150online.com/forums/ar...then-some.html

 

4wd actuator

 

I was afraid of that. Only thing I haven't checked is the vacuum lines where there not so visible

 

wow heaps of great IWE information in that link, great thread thanks very much

 

Its not a bad fix, I had mine done this spring. Cost me roughly 680 cdn

 

Just unplug the vacuum lines and cap them off. might lose a tiny bit of mpg, but most folks see no difference.

 

Where is the best place to do that? At the wheels is a pain this time of year, but at the firewall might be ok, and what to use as a cap?

 

My 14 started doing that about a year ago. Shop told me it was probably just a leaking vacuum line. But I ended up needing a new IWE on the right side. It wasn't too expensive

 

If you read through this link, at the end it will give you an idea what to do and which parts to remove and plug. But for simplicity's sake it says to remove the hose between the vacuum source and the check valve and then to cap both ports where you removed the hose from.
This TSB refers specifically to trucks with the 4-auto system. But the vacuum system uses the exact same parts and functions the same. So aside from the possible minor hit to mpg, there are no ill effects from doing it to a truck with the standard t-case.
The Ford part number for the caps is W716372-S300. But they are literally just little rubber caps. So you can source them from wherever you choose. Just know that for some reason that part number is listed as a "bolt" in some catalogs. But it is definitely just a rubber cap.

https://static.nhtsa.gov/odi/tsbs/20...05305-0001.pdf