STRANGE "GROWLING" NOISE AND VIBRATING AT ACCELERATION

[Oostenstein]

I owe a 2020 GMC sierra 2500hd SLT 4wd 6-speed automatic 6.6l V8 GAS crew cab, and at roughly 70,000 miles it has started making a strange growling/buzzing noise that sounds like its coming from under the passenger side floor board.
It kind of power surges my truck when it does it and feels like its "jolting" when it does it, but Then it goes away.
Seems to start around 45mph at minimal throttle but it goes away instantly when you left off the throttle. . It is completely random when it'll do it but mostly when I accelerate, or at higher RPM's.
At first I thought it might be the transmission, transfer case, or something. Then I thought it was a heat shield rattling. No luck. 

I took it to a mechanic and they thought it was my muffler, so I had a brand new exhaust put on with a new muffler. They also thought that it might be a u-joint in the driveline that was starting to seize up, but after inspecting everything they havent had any luck. Mechanics pulled rear driveline and checked u-joints. left the rear driveline out and drove it in 4x4 to see if it was out of balance or vibration was still there. balanced and rotated tires and it's driving me nuts! The noise has been an absolute ass kicker trying to track down. 

Any luck with this would be greatly appreciated. 

[Another JR]

Torque converter?

[newdude]

Converter or fluid pump in the transmission?  Any chance you've got the ability to monitor torque converter slip speed or transmission data at all for pressure?

[Jettech1]

Can you feel the vibration when sitting in park and just revving the engine?  Have you tried putting it into Drive, holding the brake with your left foot and start bringing the RPM's up slowly?  Yes a great way to do a burnout lol but I'm curious if it is in fact a converter issue or a balancer issue.  I'm not sure what the stall speed is from the factory converter but I bet @newdude does.

[GMCustomerService]

On 3/3/2023 at 7:25 PM, Oostenstein said:

I owe a 2020 GMC sierra 2500hd SLT 4wd 6-speed automatic 6.6l V8 GAS crew cab, and at roughly 70,000 miles it has started making a strange growling/buzzing noise that sounds like its coming from under the passenger side floor board.
It kind of power surges my truck when it does it and feels like its "jolting" when it does it, but Then it goes away.
Seems to start around 45mph at minimal throttle but it goes away instantly when you left off the throttle. . It is completely random when it'll do it but mostly when I accelerate, or at higher RPM's.
At first I thought it might be the transmission, transfer case, or something. Then I thought it was a heat shield rattling. No luck. 

I took it to a mechanic and they thought it was my muffler, so I had a brand new exhaust put on with a new muffler. They also thought that it might be a u-joint in the driveline that was starting to seize up, but after inspecting everything they havent had any luck. Mechanics pulled rear driveline and checked u-joints. left the rear driveline out and drove it in 4x4 to see if it was out of balance or vibration was still there. balanced and rotated tires and it's driving me nuts! The noise has been an absolute ass kicker trying to track down. 

Any luck with this would be greatly appreciated. 

This is certainly not what we like to hear, Oostenstein.  Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2020 GMC Sierra 2500 HD. To do so, please send an email to [email protected] with ATTN: Oostenstein/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
 
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
www.gm.com
 

[arca07]

 I have the same problem on a 3500 dually was under again tonight and there is a heat shield after the muffler and tucked up under the bed itsvery thin and attached with push in buttons this was part of the rattle then I found the rear disk shroud tapping on everything with a little rubber Mallett made the sound so took off wheels and removed the backer plate back to the road that was part of the sound also the deper rattle still have the vibration in the floor though and it's only at acceleration and up hill mostly 

[slmdtoy]

any solution to this issue  ? 

it’s driving me nuts  

chevy has no idea and says the  truck is fine. 

the growl is getting worse. it use to do it at 65mph only now it’s more often and after 4th gear . 

 

 

it also feels like i’m getting  rear ended every time it shifts from 2nd to 1st 

 

2020 6.6 gas 6speed Custom 

[Bruce proko]

On 3/8/2023 at 10:10 AM, GMCustomerService said:

This is certainly not what we like to hear, Oostenstein.  Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2020 GMC Sierra 2500 HD. To do so, please send an email to [email protected] with ATTN: Oostenstein/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
 
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
www.gm.com
 

 

[Bob6805]

i’m having the exact same issue with my 2019 chevy silverado 2500HD LT

I also get the same response from dealer they can not find anything.  My issue started after the fluid maintenance the dealer performed

[sapoCD]

On 3/3/2023 at 6:25 PM, Oostenstein said:

I owe a 2020 GMC sierra 2500hd SLT 4wd 6-speed automatic 6.6l V8 GAS crew cab, and at roughly 70,000 miles it has started making a strange growling/buzzing noise that sounds like its coming from under the passenger side floor board.
It kind of power surges my truck when it does it and feels like its "jolting" when it does it, but Then it goes away.
Seems to start around 45mph at minimal throttle but it goes away instantly when you left off the throttle. . It is completely random when it'll do it but mostly when I accelerate, or at higher RPM's.
At first I thought it might be the transmission, transfer case, or something. Then I thought it was a heat shield rattling. No luck. 

I took it to a mechanic and they thought it was my muffler, so I had a brand new exhaust put on with a new muffler. They also thought that it might be a u-joint in the driveline that was starting to seize up, but after inspecting everything they havent had any luck. Mechanics pulled rear driveline and checked u-joints. left the rear driveline out and drove it in 4x4 to see if it was out of balance or vibration was still there. balanced and rotated tires and it's driving me nuts! The noise has been an absolute ass kicker trying to track down. 

Any luck with this would be greatly appreciated. 

.did you find out what was causing this? Same thing on 2020 2500

[Bruce proko]

On 3/6/2023 at 3:22 PM, Jettech1 said:

Can you feel the vibration when sitting in park and just revving the engine?  Have you tried putting it into Drive, holding the brake with your left foot and start bringing the RPM's up slowly?  Yes a great way to do a burnout lol but I'm curious if it is in fact a converter issue or a balancer issue.  I'm not sure what the stall speed is from the factory converter but I bet @newdude does.

my truck had a shutter also i have a 2020 2500 hd with 6.6 gas and my problem was the torque converter i got it changed and noises are all gone 

[Another JR]

25 minutes ago, Bruce proko said:

my truck had a shutter also i have a 2020 2500 hd with 6.6 gas and my problem was the torque converter i got it changed and noises are all gone 

Was this diagnosis and replacement done under warranty?

[Bruce proko]

no mine wasn't under warranty i had to many km 

[Fallguy76]

2020 Chevy 2500 6.6 Gas. Im having the same issue. Was the problem found or any type of resolution ?

[Kevin3]

On 3/1/2024 at 1:42 PM, Bob6805 said:

i’m having the exact same issue with my 2019 chevy silverado 2500HD LT

I also get the same response from dealer they can not find anything.  My issue started after the fluid maintenance the dealer performed

Any solution found to this yet? Have the same thing going on, driving me insane