Rear end clunk on AT4 HD

NaturallyAspirated · December 31, 2022

My beloved truck did that very occasionally over the first couple thou miles. At 12,000 miles now and it’s been completely gone.

Pryme · January 1, 2023

I seem to hear a muted clunk type sound around turns but mine sounds more in the front. It’s only noticeable if the radio and fan are low. It doesn’t seem it’s even always in the same spot. Not worried at this point though because it’s not every turn. I’d say maybe 10-15% of turns. Nothing over rough roads that I can tell.

Edited January 1, 2023 by Pryme

Jettech1 · January 1, 2023

16 hours ago, Pryme said:

I seem to hear a muted clunk type sound around turns but mine sounds more in the front. It’s only noticeable if the radio and fan are low. It doesn’t seem it’s even always in the same spot. Not worried at this point though because it’s not every turn. I’d say maybe 10-15% of turns. Nothing over rough roads that I can tell.

I have the same thing but I feel it in my steering wheel.

Pryme · January 2, 2023

7 hours ago, Jettech1 said:

I have the same thing but I feel it in my steering wheel.

What do you think it is? Around turns?

GMCustomerService · January 9, 2023

Hello everyone, this is certainly not what we like to hear. 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 trucks. To do so, please send an email to [email protected] with ATTN: [Forum Username]/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.

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Edited January 9, 2023 by GMCustomerService

Pryme · January 9, 2023

Has anyone contacted the above information? Just making sure it’s a legit link and GM service.

HDroofer · January 9, 2023

I had the same thing with slow turns and in reverse for the first 7-800 miles but seems to have gone away now

Mass2500HD · January 10, 2023

3 hours ago, Pryme said:

Has anyone contacted the above information? Just making sure it’s a legit link and GM service.

I’m wondering the same thing. And my worry is that my clunk is not predictable. So I can just sense a never ending back and forth with a dealership. I’m trying to pinpoint some spots that mine always does it, but then I have to drive an hour to my dealer that I bought from. Dealers within 10 min of me are all dbags that will not put any effort in beyond normal oil changes unless you bought from them.

Gasman03 · January 13, 2023

On 12/28/2022 at 12:13 PM, ttowntwostep said:

Just bought a 2023 2500HD AT4, 157 miles on it and it's doing the same thing. You can rock it gently by the bed and it feels like something is loose with the axle. Haven't taken it to the dealer yet. The 2015 GMC I traded in was still solid as a rock after 8 years.

I also recently purchased a 2023 2500HD AT4. I started hearing the noise in the rear of the truck before I put 100 miles on it. It is only noticeable with slow speed suspension rock or slightly cambered turns that produces undercarriage clunks. My truck is currently in the shop for the second time, with less than 500 miles on it. To state this is frustrating, is an understatement!

Pryme · January 13, 2023

1 hour ago, Gasman03 said:

I also recently purchased a 2023 2500HD AT4. I started hearing the noise in the rear of the truck before I put 100 miles on it. It is only noticeable with slow speed suspension rock or slightly cambered turns that produces undercarriage clunks. My truck is currently in the shop for the second time, with less than 500 miles on it. To state this is frustrating, is an understatement!

In the shop twice for this clunk sound? Please keep us posted on what you find out.

Mass2500HD · January 13, 2023

Yes please, my dealer is an hour away, so if someone gets a good lead on the culprit, it saves me multiple trips.

Pryme · January 13, 2023

I’ve read some people having less than right U bolts. I wonder what the spec is for the torque settings on those nuts?

@newdude I bet has access to those torque specs?

newdude have you seen any trucks with random clunks as the truck goes around turns at low speeds and say over off camber turns into driveways etc?

Jettech1 · January 14, 2023

5 hours ago, Pryme said:

I’ve read some people having less than right U bolts. I wonder what the spec is for the torque settings on those nuts?

@newdude I bet has access to those torque specs?

newdude have you seen any trucks with random clunks as the truck goes around turns at low speeds and say over off camber turns into driveways etc?

I can't remember where the post is, this is where you shine bigtime because you save all of this stuff. Anyhow one person was having clunking issues and took a pic of the U bolts on the springs. I swear I could see light between the U bolt and the springs. I'm wondering if maybe these U bolts aren't tightened to specs at the factory, or with the suspension settling in just a hundred miles or so they are loosening up. All of this clunking noise has to have something to do with the either the springs attachment point or the U bolts. I can't think of any other way this noise could be replicated. What are your thoughts Pryme?

Pryme · January 14, 2023

1 hour ago, Jettech1 said:

I can't remember where the post is, this is where you shine bigtime because you save all of this stuff. Anyhow one person was having clunking issues and took a pic of the U bolts on the springs. I swear I could see light between the U bolt and the springs. I'm wondering if maybe these U bolts aren't tightened to specs at the factory, or with the suspension settling in just a hundred miles or so they are loosening up. All of this clunking noise has to have something to do with the either the springs attachment point or the U bolts. I can't think of any other way this noise could be replicated. What are your thoughts Pryme?

I’ve been thinking about it and it would seem based on what I’ve read that it would have to be the leaf and/or u bolt assembly area or the shocks. I’ve read some people saying the shocks caused low speed clunking. I’ve personally never had that happen though on any vehicle so I’d be more inclined to think it was the leaf or ubolt assembly.

I can hear it depending on the turn or just the angle or dynamics of the turn. I notice every little sound it drives my wife nuts. She would never notice any of this stuff.

Jettech1 · January 14, 2023

2 hours ago, Pryme said:

I’ve been thinking about it and it would seem based on what I’ve read that it would have to be the leaf and/or u bolt assembly area or the shocks. I’ve read some people saying the shocks caused low speed clunking. I’ve personally never had that happen though on any vehicle so I’d be more inclined to think it was the leaf or ubolt assembly.

I can hear it depending on the turn or just the angle or dynamics of the turn. I notice every little sound it drives my wife nuts. She would never notice any of this stuff.

I notice every little sound and feel as well but I feel or hear nothing out of the rear end. I only have that nagging front end glitch that I will take care of myself. I hate dealerships. Sorry to say but they hire the ones who will work for lowest amount of money that are expendable at anytime. Wouldn't it be great to have a dealership that hired only the best of the best? Paid them great money, were able to troubleshoot any problem and have it fixed it no time....I would personally drive hundreds of miles for a dealership like that to have my truck worked on. Even for just an oil change.