Loud Grinding noise on 2004 Ford F-150

Loud grinding noise in drive been told possible transaxle for 4x4 trying to engage by its self. stops if I switch to 4H any others have this problem and if so what was the fix

Asked by for the 2004 Ford F-150
The TSB number is OS 06-8-15 (publication date April 18, 2006). The problem was caused by the IWE solenoid, which is located on the passenger side firewall, just below the hood. Water coming off the windshield was running onto the solenoid and causing a short. The solenoid controls the vacuum lines that control the shifting between 2WD and 4WD. A short in the solenoid causes a change in pressure in the vacuum, which starts the shift into 4WD. The grinding occurs because the change in pressure is not sufficient to fully engage the 4WD - the system is left half way between 2WD and 4WD until something else happens, such as applying the brakes or manually shifting into 4WD High, Check your fuses the water might be blowing it.
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If this has been doing this for a while it may have damaged the IWE actuator also small gears with teeth within the IWE Usual fix is a new Vacuum IWE solenoid and 2 new IWE's for the front wheels same part number for left and right IWE is integrated wheel end