Here's what I got. 2005 F-250 crew cab with the 6.0, almost 200,000 miles. This only happens on the highway. I have a high pitched whining noise but it's very faint. I notice the littlest things on my truck and can usually figure out what it is.. If you have the radio on you cannot hear it.. If I let off the gas it goes away.. I'm leading towards a bearing but the letting off the gas fix is throwing me off.. And sometimes it doesn't do it all. For instance, it's been a few days since I've heard the noise, and it usually does not last long. I first noticed it on my way to the ranch about a month ago. What do you guys think??

 

and yes it's 4x4

 

I don't know what it is. But here are some ideas of things that often whistle.

A turbo boot is leaking.
The turbo wheel is wobbly and rubbing, or a bearing in the turbo is going bad.
The coolant degas bottle is blowing excess pressure.
The serpentine belt is slipping.
An alternator or A/C bearing is failing.

I suppose those are close to order of likelyhood, not having heard it. Another one is just the engine cooling fan, but I assume you know what that sounds like and hear it often.

 

what does your howl sound like. I have been chasing my own noise for 1.5 years. mines sounds like a raunchy mud tire howl, but quiet enough you can barely hear it.

 

how about attempting a video recording? might help to identify
can you tell for certain wether its coming from under the hood?

just spitballing but is 4x4 engaged? could it be and the light is bad? can you spin the front drive shaft by hand when the selector is in 2wd position...?

another idear... maybe gear whine from your rear end?
have had a rear end that whined when you put your foot in it but was quiet when let off...

details details details...


xtof

 

My truck (in my sig) has been doing that for the past week or so. It would squeak/chirp on start-up, and I could hear it a little bit when driving. Taking my lead foot off the skinny pedal would make it stop. Well to make a long story short, I put a new idle pulley on last night. This morning when I started the truck up at 5:15 am..... quiet. The drive in to work was quiet too. I'll see what she does when I fire her up cold when I leave work... Your 6.0 may be different, but so far I think that was the problem with my 5.4 gasser.

 

Hmm must remove serpentine belt and check idlers. 115,000 miles on them and belt

 

I just replaced the idler pulley a few months ago.. i know what that sounds like, definitely not it.. the noise is definitely coming from the front of the truck.. the only way to describe it is a very high pitched whine like those dog whistles

 

These are good ideas, sounds like im dealin with one of these issues.. thanks!! Is there anything I can do to prevent my turbo from going out if this is the issue, or should i just plan on buying a new one when it goes out??

 

I'm not sure if there is any maintenance you can do to prolong a turbo life. If you've made it 200k miles, you've done pretty good. If you can determine that the noise is coming from the turbo, you can pull it and try cleaning it, and at the same time measure the wobble in the wheel. You want to check axial play and end play. I'm not sure of the acceptable play at the moment, but the values are probably around here somewhere. It could be that just cleaning it will stop the noise. Check the 6.0 diesel forum tech thread for info on how to pull and clean it.

You should also ask a moderator to move this thread to that forum for better advice from the experts.