Hey guys. I have recently noticed a "humming" coming from the front end of my '05 5.4l 4x4. Sounds kind of like a groan in the front differential. At lower speeds it is deeper and more noticable and as speed picks up it becomes higher pitch I guess and although I still know it is there, it is not as noticable.

When I shift to 4HI the noise goes away. But as soon as I shift back to 2WD it is back. This happened to anyone else? Any ideas?

 

After doing some more research I think its the IWE solenoid. Guess I am going to buy a new one tomorrow and go from there. Hopefully nothing is damaged already.