Dealer can't hear it. Rode with them and they still can't hear it. I may try to clean the throttle body and see if it does anything.

I have a 2018 5.0 V8, and if it's the same noise that mines experiencing (what sounds like a whistle or whining when the transmission upshifts), when they DO hear it, they will just say that it's normal................which BTW is complete BS.

Its the new fake turbo noise they are putting on the V8 trucks ;-)

Dealer service manager said it sounded like his 2015 EcoBoost - I said it was a V8 and he bit his tongue, but seemed eager to help regardless. The tech couldn't hear anything. They said bring it back on Monday and they'll keep trying.

I brought it home and opened the hood and noticed the airbox lid not secured properly. I tried to fix it and noticed it to be fairly difficult to get the male plastic teeth into the female grooves. I think this might be the answer and will confirm tomorrow on my way to work.

Check your air box lids - kinda crazy how difficult it is to properly seat it unless mines defective.

Drove to work this morning and it still whistles... back to the drawing board and the dealership on Monday.

I was 'playing' with the whistling noise a bit today. And to be clear, by whistling noise I mean a fairly high pitched noise. Similar to having a rock stuck in the brakes (not it's not that). I put the truck in manual mode so I could hold the RPM right around 1600 - 1700 where I hear the noise. The truck has to be in drive to hear the noise. The second I goto neutral it stops (while still moving and holding the RPMs constant). I had tried this previously, but not while moving.

Next time I will try in 2nd gear vs 3rd gear at 1600 - 1700 RPM.

For the brains on the site I ask this:

If I am working off an air leak theory, either intake or exhaust or other, is there a major difference in the air flow if the truck is in drive VS neutral while holding the exact same low RPM of 1600 - 1700?

Heard it in both 3rd and 4th over the weekend. The same RPM range 1500 - 2000. Seems to be more pronounced going up a hill.

I ordered a new throttle body and will install when it arrives to see if that is the issue. I checked for vacuum leaks with carb spray and found nothing. If the new TB doesn't work I'll consider it a normal inherent characteristic. I'll report back in a week or so.

I have a whistle when in neutral. I was going through a drive through and heard it bouncing off the walls. Anyone have this noise in neutral?

Only while in N? Idle?