Buzzing sound in dash

[Tunatruck]

My truck is a 16 Laramie ram megacab cummins 4x4 dually. I’ve owned every cummins gen except the 2nd and never had this problem. It’s barely noticeable without my trailer unless I give it tons of throttle. When pulling a heavy load the buzzing sounds like it’s coming from behind the Speedo and it’s louder the harder I accelerate, but can always be heard under a load. What is it? Fix?

 

[Random_Walk]

Could just be something that got loose enough to vibrate against something, and under load, the vibrations would exaggerate enough to make it louder... hate to say it, but you may have to do a bit of dashboard spelunking to make sure nothing is chafing back there.


(I got that noise once, but in my case I forgot I had change loafing around in the ashtray, and the sound carried up behind the dash. I'm sometimes dumb like that.)