TexasBoy23

there are three check valves in the vaccuum lines. Check those. Pull them out, (remember which way they are installed). blow in each end of them, you should only be able to blow through in one direction. If you can blow through in both directions, its bad. They are cheap and easy to check, thats where I would start.

If they are all good, you can visually check the hoses running to your IWE for holes, tears, cracking, etc. I replaced all of mine about two months ago with stock vaccuum hose from Oreillys.

Go to the link below.... it will tell you everything you ever wanted to know about your 4WD system.


https://www.f150forum.com/f72/how-di...m-esof-186872/

60DRB

Here are the usual links for fixing the all too common 4x4 isssues.

ttp://www.f150forum.com/f72/how-diagnose-your-4x4-system-esof-186872/

http://www.ford-trucks.com/forums/83...then-some.html

http://www.f150online.com/forums/2004-2008-f-150/360269-iwes-removal-replacing.html

ccbruin

Exact same thing happened to me yesterday. Like everyone is saying, its the IWE system. I had a hole in one of the lines all of a sudden? I taped it up for now, and I no longer hear the leaking air sound, but still have not tried it back on the highway where i heard it.

jamie930

pull the vacuum lines off the solenoid and see if the noise is still there. Pulling the lines will engage the IWE. If the noise goes away look the the IWEs

I would also leave that line pulled off if it is the IWEs to prevent any further damage to the IWEs

cgp4312

I unplugged the vacuum lines off the selenoid and i haven't heard the noise yet so does that mean I have a leak in one of the lines or check valves

jamie930

most likely. The IWE can partially engage cause the noise. Pulling the line fully engages the IWE

cgp4312

Ok thank you

techrep

iTrader: (1)

There are check valves in the system that need to be checked too...

cgp4312

I checked all the check valves and found a bad one so I replaced it and it wirked for a few days and then I started getting that sound again so I thought a got a bad check valve or something so I replaced it again and that one did the same thing after about a weeks worth of driving is there something that could be causeing them to go bad or am I just having bad luck I'm gonna try getting a new one tomorrow but they are hard to find around here since they are so small

VTX1800N1

Follow this link as you were told. I explain the system, how to diagnose it, and how to repair it. Throwing guesses and parts at it will get you nowhere and quickly empty your wallet.

https://www.f150forum.com/f72/how-di...m-esof-186872/