What the heck did i do to my truck!??!?
 

Before I started working on my truck friday evening everything was fine. Then I put on a 2.5" leveling kit, and when I put it back together and took it for a test drive there was this god awful scraping/grinding noise in the right front, so I took it back apart this afternoon and checked everything out and it all looks good. Everything turns as it should, so I put it back together and there's that god awful noise again, but it rides smooth as silk. Here's where it gets odd, it only does it going forward, and during acceleration. It doesn't do it in reverse, or when coasting, and doesn't seem to do it when the 4wd is engaged, but i haven't gone very far or accelerated that fast with the 4wd engaged. If I accelerate like an 80yr old woman i can keep it from doing it, but as soon as you give it the slightest amount of gas it starts this. here's a video, not the greatest because i didn't have anyone to ride shotgun and take it for me, but you can tell when I let off the gas. Oh, and I checked the dust shield for the brakes, and no its not rubbing the rotor.

http://vid194.photobucket.com/albums...508_204524.mp4

Are you running the stock wheels and tires?

for now

Is your truck 2 wheel or 4 wheel drive?

It's 4WD

Is it constant scrape, or intermittent; I.E. the sound speeds up the faster you go. (If that makes sense)

That's irritating. Awful noise.

Low vacuum to IWE for any number of reasons. Vacuum line leak, bad check valve(s), failed IWE.

High vacuum = hubs disengaged (2wd selected)
No vacuum = hubs engaged (4wd selected)
Low vacuum = hubs trying to engage but vacuum not low enough to fully engage = grindy noises. (2wd selected)

Low throttle input = high vacuum = no grindy noises
High throttle input = low vacuum = hub trying to engage = grindy noises.

Switching to 4wd removes all vacuum to IWE's which locks in the hubs (like it should) and the grindy noise stops.

Short term fix: Remove vacuum line from intake (4.6) or brake booster (5.4) that goes to the IWE solenoid on the passenger firewall and plug the intake manifold side it with a tight fitting screw. With 2wd mode selected on the dash, this will cause the hubs to be engaged and it will turn the halfshafts, but the transfer case will not be engaged. It will drive normal until you can test/replace the IWE.

Remember to get it aligned, don't know if it would be the cause for the noise, but needs to be done regardless.

I have a wheel bearing going out and have similar noises. The spacers may have just brought out the noise from a previously worn bearing. Could be CV joint going bad too.