I appreciate all the work you have done on the IWE issues it has been very informative. I have an '08 F150 FX4 Screw that I believe is experiencing this issue. I waas on the interstate yesterday running about 75 mph when I heard a light grinding or hissing noise. It went away and then came back and went away. This occurred on my 125 mile trek to hunt. On my way home I experienced the noise again and I exited the interstate. Upon approaching the stop sign the noise continued and when I turned right I heard a clunk and then the noise went away. I switched to 4x4 Hi and then back to 2wd Hi and I made it home with out additional noise. Being an 08 I have the ssolenoid with the cover. I made a 800 plus mile trip last weekend and noticed my mpg was BAD! 14 to 15 on the highway. What suggestions do you have? Check valves, vaccum leak, actuators? Please let me know. Thanks again for your work and help!