Hello all! I have a 2007 FX4 5.4L and for the past couple of weeks I've had this god awful intermittent scraping metal/grinding sound coming from the front drivers side. Brakes/rotors are fine, so my initial thought process was a rock got stuck in the dust shield. Nope. Absolutely nothing triggers it. Sometimes it does it while accelerating, sometimes it does it while braking. Sometimes it'll do it for 10-30 seconds, other times it'll do it for a full 20 miles. Sometimes, it'll go a 50 mile round trip without a sound. Thanks to this forum I stumbled upon the IWE situation so the next time it happened, I threw it into 4H and instantly the sound stopped. I did come to a complete stop after the switch and the braking was pretty grumbly/clunky but was fine going forward. I've continued to use this method each time the noise starts, switching to 4H and then switching back out after a little while. Since doing that, braking has now continued to be clunky, but only at the very last fraction of a second before the vehicle comes to a complete stop I checked the vacuum solenoid and corresponding hoses and all seems to be well (don't have a vaccum pump so was unable to check pressure) but with wheels off and the vehicle off, wheels are locked. Upon starting the vehicle, they spin freely. I'm prepared to buy a new solenoid and line system, but are there any other areas I should troubleshoot first? I'm also not seeing a check valve anywhere in the line, is this normal? Any and all help/info is much appreciated! Thanks!

 

See if this thread helps:

https://www.f150online.com/forums/ar...then-some.html

Also check the CV joints, front end parts, and front brakes, that could be the source of the clunking brakes.

 

being fairly new to these 4x4 trucks i had a similar situation a couple of months ago.

until i get all the parts and tools to go through and diagnose/repair the entire system in depth this winter, my temporary solution was to disconnect and plug both sides of the vacuum connection up near the intake manifold. (not at the actual manifold connection, but the one that lies about halfway between the manifold and solenoid.)

i drive it in only in 2H so that the transfer case is not engaged. this is important because 4H should not be used on normal dry pavement. in 4H of 4L the transfer case locks the front/back driveshafts together and that is the "binding" you feel on dry pavement.

if i'm ever in a situation where i need the 4wd, i will be sure come to a complete stop before switching to it. (i won't try SOTF with the way i have it rigged.)

anyway this has completely solved my noise problem.

of course, the driveshaft, differential gears, and halfshafts are constantly turning, but i haven't noticed any real adverse effects. i'm sure gas mileage is probably less and there is more wear and tear on the components, but the truck rides like normal.