*sigh* Yes, another grinding sound issue
 

Vehicle
2008 Ford F-150 SuperCrew FX4 5.4L Flex Fuel

So I’m trying to figure out an interesting problem on my truck. After a few minutes of driving, I hear a metallic-like grinding sound. Not a mechanical grinding, but more flat metal on flat metal type grinding. The frequency of how often it happens, is tied to overall wheel speed – Less rotations on the tires the slower the frequency of occurrence. After about 30 mph it happens fast enough, obviously, that I can’t hear it anymore.


Heres a few requirements to get the issue to occur:

Must be warmed up
Louder when using the brakes
Seems to happen in Drive only, not reverse (though every time I’ve tried it in reverse, it hasn’t been warmed up yet)

I’ve “gently” powerbraked it to see if it was the rear end, with nothing resulting. I’ve had a mechanic co-worker of mine ride in it, listen to it, and walk next to it when the sound happens. Zero ideas. Though he thinks it isn’t my Wheel Hub/Bearing assembly. No pops or clicks like it might be the driveshaft.

Lifted up the front end, rotated both tires freely, checked for up+down wobble, and side-to-side, with nothing out of the ordinary – further suggesting it might not be a hub assembly. Now, it could only happen under load (I.E. weight of vehicle) I have no clue.

I’ve also read about the IWE issue. So, Tried engaging 4-wheel High after hearing the sound, but no change after high was engaged. Stopped and shifted to neutral and back just to confirm, still no change. Unless I have something in the vacuum lines or a component is already shot, it shouldn’t be the drive hub thing.

Also, Just did the brakes about a 2 months ago. New calipers, rotors, and pads on all 4 corners, bedded properly, and all installed correctly. I haven’t had time to check yet, but from a quick glance there are no signs of odd or premature wear. I’ll be checking thoroughly on Sunday.


I wouldn’t be OVERLY concerned, but the sound is getting progressively louder over time. Not at an alarming rate, but still. This is going to drive me insane until I figure this out. I don’t mind spending money on what needs to be fixed/replaced, but I know throwing parts at it won’t get me anywhere. I at the VERY LEAST need it to get me through the end of the month, until I move – Then I’m walking distance from work.


Any advice?

Have you checked your front diff? Transfer case?

Unforutnately, I don't know how to specifically check. Transmissions and T-cases aren't something I've dealt with. Changed the clutch in a Manual, but thats about it. I learn as I go. Any tips or tricks?

Chk disk brake dust plates for warp and tight?? Was prob present before brake job?