Fine vibration/buzzing related to 4wd
 

I've had a very fine, subtle vibration that comes and goes. It's hard to explain but basically the drivetrain isn't running smooth and has like a high frequency low amplitude vibration. Feel it in the floor boards and seat basically. It's pretty subtle, often when I point it out to passengers they claim to not notice it but I'm so tuned in I notice it immediately. It's driven me crazy trying to figure out the cause but finally one thing that that I've figured out is that by engaging the 4wd it clears right up. Now that I've figured that out when a passenger can't notice the vibration all i have to do is put it in and out of 4wd to demonstrate before/after and they immediately notice the difference in smoothness when in 4wd. There is a slight delay in the vibe coming back after going in to 2wd I assume while the 4wd is disengaging. This seems very odd to me, as I'd think if anything the addition of more running gear in the drive line could only make it worse? But it's very definite when it occurs that I can put it in 4wd and it clears up, back to 2wd and the vibration comes back. I'm concerned about wasting my time with the dealer not being able to repro the issue. Any thoughts or ideas on this one from the F150 community?

I bet you have an IWE not disengaging all the way.When you take it to the dealer,be shure to show them exactly what it's doing.Could be a vacum problem,or and IWE itself.

Anyone else ever experience this? Brought to dealer just before 36m warranty expired and everything checks out according to them. Thing is, it seems to go away in the summer and now that it's getting cold again its flaired back up.

I had a vibration issue with mine along with a clicking sound and rough ride. The dealership replaced the steering rack and IWE solenoid last week and it fixed the issues.

Thanks for the feedback! Can you describe the clicking sound and when you would hear it? Was the repair done under warranty, curious what the cost would've been if not?

I get clicking when I turn the wheel while stopped. I have a 4" lift installed which seems to get blamed for anything which might be remotely possible... including this clicking.