Front end noise - popping sound

[jeepfix]

05
5.4 3V
4x4
105,000 miles
no prior history of issues

I've been searching this site and the f150 sites with no luck. The noise has progressivly gotten worse since 8-2011. Car is in 2wd mode, when the car has been parked either overnight or for a few minutes and when first backing up a pop noise is heard from the front left to front-center. Sometimes it's a single pop and other times it'll pop 3 times or more. Then when putting into drive, it'll pop and click like cv joints but just for the first few feet. No noise while driving except when occationally going over speed bumps or pulling into driveway.

Ford Mechanic friend heard the noise and said it could be ball joints, but as I was leaving it popped three times on a level driveway. He said that's not ball joints. It could be something in the 4x4. Tried parking it in 4x4 high. No noise when backing up in 4x4 high.

The popping noise is like a metal to metal sound. It's loud. Can be heard inside the car our outside and from some distance away. It's one pop at a time in a pretty quick succession.

It will pop everytime I back out of my level garage except when in 4x4 high. (CORRECTION). Noise occurs in 2wd mode or any 4x4 mode.

 

[sgtowing]

It sounds like the the front hubs. I think they use vacuum to keep them disengaged. It sounds like you are loosing the vacuum that keeps them disengaged when it is parked. Try this, when you get in it, start it up and let it sit and idle a couple of minutes to build vacuum. Then go ahead and move the truck and see if it still does it. If no popping, then it's your hubs engaging. You would have to see where you are loosing vacuum at that point.

 

[jeepfix]

Update: the issue has gotten much worse sounding. Now pops and clicks backing up, pulling forward, turning the wheel and not turning the wheel. Plus 4x4 mode now makes no difference. I ordered a service CD and think it's the cv joint on drivers side. Will update later with more news.