Here's my story:

I have a 2004, new body style F150, 4x4. I was driving down the road a couple months ago, at about 55-60 mph, when I heard this "buzzing/grinding" noise...coming from somewhere! I drove another two miles wondering what the hell the noise was that was coming from my truck! So, when I pull up to the traffic light; Clunk! Something in the Left Front wheel area fell into place. I said, "Well, That damage is done..." So I kept going home another three miles. A few weeks later I heard it again, so this time I came to a Stop as soon as heard it and realized what was going on. Clunk! Put it in park, got out, turned wheels so I could look in wheelwell area, nothing was loose, missing, broken, out of place; all looked good. So, I kept going about my business. About two weeks ago I got on to this here F150online forum and started reading about what this noise and problem was. I had read some Great forums on just about exactly what my truck was doing. Just the other day I wanted to go off roading. I put my truck in 4x4 (floor shift) and went up this little bank. Truck's rear wheels were spinning out! So here I am, just about stuck, Pride wounded that my F150 can't make it up this two foot bank, backing down this hill, realizing that my truck's 4x4 does not work. I'm pissed, lol. So next day I changed the IWE (inner wheel end) vacuum solenoid (mentioned in forums.) My part number of 6L3Z*9H465*B-OEM. Replaced that and now I have vacuum at wheel hub, which I didn't before (when it wouldn't go up the hill.) Now I do more diagnosing and get my truck jacked up on jack stands and go through the motions: 2wd-rear wheels spin and none of the front ones...4wd-passenger front is not spinning but both rear wheels are; driver front axle shaft IS spinning but making a hellashious grinding/rattling noise! So, needless to say, something isn't working in my driver front locking hub area. Next day I called Ford dealer needing this IWE (7L1Z*3C247*A - my part number.) I go to change it that night and get everything torn apart to realize the gear in this IWE is half stripped out as well as the mating/adjacent gear on the wheel hub! So next day I called Ford dealer needing that gear, which came with 6 wheel studs, speed sensor cable and gear, as an assembly (4L3Z*1104*AB-my part number.) All I had to do was swap out bad for the good. Piece of cake actually! Short story,...got everything back together, tried everything out on dirt road, everything worked! Made it up that two foot hill the next day too! That's right! Pride restored! It cost me a total of 3 parts and about $400. I recommend following TN-F150's downloadable links!!! thank you... to guide you through the process. Summary - If grinding noise occurs, check vacuum at 4x4 actuators on both sides and replace with this number (6l3Z-9E441-A) (with water hood) because my original shorted out in the first place. Hope You All can diagnose this problem on My expense!

 

Also, my truck has 124,300 miles on it when this happened.