What is this infernal flappity-dappity sound I hear?

OK this is driving me to drink'in.
At higher speeds only. 70-80 or so.
Driver side.
There is some damned flapping sound I hear.
Not metal on metal flapping but more like a plastic part flapping- slapping.
I spent hour or so and checked all door seals and even used Dow 795 silicone an all loose gaps, etc So the door surround seals are solid .
Nothing underneath, not a loose mud flap or loose wheel shroud.
Glass sidelights and seals seem tight too.
Top roof edge gasket is sealed too.

Anyone else?

 

Do you have a video or other recording of the sound?

 

Check your splash guards in the wheels well and make sure all clips are still there and functional

 

This ^

 

On your year truck, maybe the upper grille piece that attaches to the hood? The clips can be weak and allow it to rattle around in there. If it’s truly coming from drivers door, is it something inside the door card? There’s some waterproof membrane on the door in there. Not sure what else could flap around in there. There’s cab vents on the back wall that have flaps on them also, generally can’t hear them at all though.

 

Windows up, down or either way??

 

That happened to me. It was so loud at times, it sounded like it was inside the cab.

 

Did someone put zip ties on your driveshaft?

 

I roll drivers side rear window down a bit and I can't hear the flapping. Then again at 80MPH its like a 747 engine all around me.
Window glass is not rattling when observed thru mirror.

 

I'll hop on the ol creeper tonight and check those out. Obvious has something to do with wind speeds and air rushing around something.

 

The reason I ask, is that I had a similar experience when one of my rear windows was slightly open; maybe 2-3" as the most. But window closed or window further down no issues...

Drove me nuts for a couple of weeks and couldn't figure out what it was at first, but finally realized I had a very small piece of window tint on one of the back windows (at the corner) that had loosened up. It almost looked like the tiny piece was meant to have been cut off during the install but wasn't completely removed and was just left hanging. It wasn't large enough to be noticed, and we ended up finding it when we were running our hands along the window trim pieces (interior and exterior) while the vehicle was in motion.

We removed that little piece of tint that was loose and obviously meant to been removed during the install and problem solved. I would've swore though that it was a piece of trim flapping around as loud as it was though...

Anyhow, good luck on finding resolution soon!!

 

You should also hear the pitch change on the highway in left/right corners but if on drivers side you can feel it slapping the bottom of the truck at higher speeds