This is getting frustrating. My '05 fx-4(5.4l-v8) is making noise from the front hub only under load when moving along in O/D. I recently installed a new IWE solonoid and thought my problems were done for a while.
I've run smoke thru the vacuum system and can't locate any leak. What would be the reason for a loss of vacuum at those speeds? Wouldn't this problem show up at other times?
The noise comes from the driver's side front hub....I could really use a suggestion or two from the forum!!!!

 

Could be a bad IWE on that side, not holding the vacuum and is partially engaging. That's where I would start looking.

 

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

 

Found it!!! The passenger side accuator does not hold vacuum for even 1 minute, while the driver side holds 20" forever. Why the noise comes from the driver side is a mystery. Although now thinking about it, the right side not holding vacuum probably bleeds off the left side.....