2020 Gmc 2500HD Engine buzzing on acceleration

[SKel]

My truck has had buzzing sound with both acceleration and deceleration for the past 3+months.  It sounds like it is coming from the passenger side front part of floor board area. Dealer looked at it 2x then changed the differential fluid and said the noise was gone. Nope. Took to a different Diesel Mechanic shop,they had it 3 days...said they hear it but can't find it. 3rd Diesel Mechanic shop said it was the turbo actuator. Bought a new turbo kit and when he got in there said the DPF sensor was bad, replaced the sensor and ran a regen; noise quieted down for about 200 miles (didn't replace turbo/actuator).  Buzzing sound is now back. Doesn't buzz when I am in N or P in the driveway and rev engine.  Anyone have a similar experience?  Suggestions on what it might be?

Edited May 20, 2025 by SKel

[motorcare]

The 2024 Duramax I had made a buzzing noise that sounded like it was coming from that same area. I'd swear that's where it was coming from but I had my seven year old grandson ride with me one day and he pointed straight at the rear view mirror/ forward collision box on the windshield. I gave the cover a little push, it snapped into position and the noise that bothered me for a year was gone forever!  

[SKel]

Thank you for the suggestion. Went out and checked the Collison Box. Unfortunately we still have the buzzing  noise.  

[Derrick Leavitt]

_{Heater hoses coming through firewall from engine into cab. Passenger side engine bay, you'll see two hoses that come through the firewall. Take a zip tie and tighten those hoses together. Noise gone forever.} 

_{I had the same issue and this fixed it in 30 seconds after dealing with it for months.}