I have a 2012 f-150 and of course the IWE’s are giving me all sorts of problems. When I put my truck in 4wd it doesn’t seem too engage the hubs and there is a terrible grind in my drives side whenever I lose traction but it also happens in 2wd when I’m driving it sounds like a tornado siren when it gets under 30° I’m at a loss I had it in the shop twice I think I just need to take it somewhere else because they haven’t figured it out just coming here to seek out any info you guys have

 

It sounds like the actuator itself/diaphragm is bad....if it was just vacuum loss in the system it should all go away when switch from 2H to 4AWD....mine broke a few years ago, on the engagement gear which is plastic (yeah plastic as part of their 4wd system, thanks ford)....would go to another shop but ask first if they are familiar with ford iwe and if not you maybe need to have dealer check