2008 6.4 sounds like a jet
 

My 2008 f350 6.4 powerstroke sounds like a jet. Only when cold start. Sounds fine at idle. On acceleration it sounds like a jet until it runs through the gears , then stops making noise. Don't know if it's the turbo or the fan clutch. Any ideas?

Aftermarket exhaust on it I'm guessing? Normal sounds of a VGT turbo(s).

all stock system

My aftermarket exhaust sounds like a jet.

Whine or high speed?
 

Is ita loud squeeling whine or sound like a high speed fan. Mine does both occasionally. I heard the high speed fan was caused by the carbon cleanout cycle not completing before turning it off. Not sure what the squeeling is but it has happened twice after pulling my trailer then sitting overnight. Very loud, only stops occassionally and changes pitch ocassionally in a harmonic way, not all over the place in pitch.
:humm:

Open your hood and take a peek behind your turbos you will have to lay on top of the engine and see if you can spot any carbon stains on your fire wall. Usually it can be the flex pipe bellows broke in the up pipes (which you can change either by pulling trans or doing in cab I do everything in cab except engine replacement) Or the cold side CAC tube has rusted through on the bottom This is the long one that is on the drivers side. These are fun to fish out. OR you could have a tensioner/idler going. These are the most common to come with a "jet sound" "high pitched" noise complaint.

when my stock dpf was failing and the truck was in regen it sounded like a jet as well.