Knocking sound from rear end 21 sierra 1500

Digger87 · May 24, 2022

Just purchased a 2021 sierra 1500 Duramax. I've owned it about 5 weeks now and it was smooth and silent up until a few days ago. I'm now getting a knock/clunk coming from the rear end. It happens when I'm driving slowly going over bumps or when turning. I did some research on this forum and narrowed it down to defective leaf springs or it's the DEF sloshing around and making noise. I jumped up and down in the bed like a crazy person. The leaf springs were silent but I did hear the DEF tank although it wasn't the same sound. Could it be anything else? I'm taking it to the dealer next week but as we all know, more often than not they are absolutely horrible at diagnosing strange noises so I'd like to make some suggestions for them.

mafd2 · May 24, 2022

Leaf springs and common. Shake the rear of the bed hard side to side and you'll hear it. Many have went to the dealer and ranges from spraying lube, greasing between leafs and even changing spring packs with only temporary fixes. Truck will sit at the dealer for days and most dealers say "it's normal". BS. That's a bad GM design. I had the same on my '19 RST and '22 LTZ. The only thing that works and the fix is called spring things. I just installed them on my '22. Thousands of GM truck owners use them and is the only product the company makes and for GM leaf springs. Easy install and works amazing and quiet as can be. I didn't even remove the wheels. Spring-things.com

Edited May 24, 2022 by mafd2

Digger87 · May 24, 2022

1 hour ago, mafd2 said:

Leaf springs and common. Shake the rear of the bed hard side to side and you'll hear it. Many have went to the dealer and ranges from spraying lube, greasing between leafs and even changing spring packs with only temporary fixes. Truck will sit at the dealer for days and most dealers say "it's normal". BS. That's a bad GM design. I had the same on my '19 RST and '22 LTZ. The only thing that works and the fix is called spring things. I just installed them on my '22. Thousands of GM truck owners use them and is the only product the company makes and for GM leaf springs. Easy install and works amazing and quiet as can be. I didn't even remove the wheels. Spring-things.com

Thank you! I won't bother with the dealer then. I'll order the spring things

mdviva718 · June 1, 2022

On 5/24/2022 at 6:38 AM, Digger87 said:

Just purchased a 2021 sierra 1500 Duramax. I've owned it about 5 weeks now and it was smooth and silent up until a few days ago. I'm now getting a knock/clunk coming from the rear end. It happens when I'm driving slowly going over bumps or when turning. I did some research on this forum and narrowed it down to defective leaf springs or it's the DEF sloshing around and making noise. I jumped up and down in the bed like a crazy person. The leaf springs were silent but I did hear the DEF tank although it wasn't the same sound. Could it be anything else? I'm taking it to the dealer next week but as we all know, more often than not they are absolutely horrible at diagnosing strange noises so I'd like to make some suggestions for them.

Hello. I went through this with my 2021 Trail boss. It is the rancho shocks. Get them replaced under warranty and the problem will be gone. A way to confirm this is to stand in the rear bumper step at each corner and bunce. You will hear it loud and clear. In fact I started to hear it in the front as well, and just had the passenger side shock replaced. Solid and quiet now.

Digger87 · June 5, 2022

On 6/1/2022 at 11:49 AM, mdviva718 said:

Hello. I went through this with my 2021 Trail boss. It is the rancho shocks. Get them replaced under warranty and the problem will be gone. A way to confirm this is to stand in the rear bumper step at each corner and bunce. You will hear it loud and clear. In fact I started to hear it in the front as well, and just had the passenger side shock replaced. Solid and quiet now.

Thank you for the suggestion but I believe the trail boss and x31 have different shocks (I could be wrong). I installed the spring things and the noise is gone so it was the leaf springs

Gangly · June 8, 2022

The TrailBoss and the X31 do have different shocks. Glad you were able to fix your leaf spring issue

Kilo · June 27, 2022

I have the same noise problem with my 2020 1500 Duramax 4WD. Took it to the dealer they said they can't find anything wrong. Took it back and had the service manager drive it. He said it is "bed shift". They tightened the four bolts

holding the bed to the frame. He said there is no fix for it. Problem is still there. Truck is still under warranty. Has anyone heard of Bed Shift? I think it's BS.

mafd2 · June 27, 2022

3 minutes ago, Jack Thaxton said:

I have the same noise problem with my 2020 1500 Duramax 4WD. Took it to the dealer they said they can't find anything wrong. Took it back and had the service manager drive it. He said it is "bed shift". They tightened the four bolts

holding the bed to the frame. He said there is no fix for it. Problem is still there. Truck is still under warranty. Has anyone heard of Bed Shift? I think it's BS.

Spring Things man. Quit wasting time at the dealer.

Kilo · June 27, 2022

ordered them just now. Will keep you advised.

Thanks much

Digger87 · June 27, 2022

2 hours ago, mafd2 said:

Spring Things man. Quit wasting time at the dealer.

Yup. These fixed my issue. Can't thank you enough for recommending them!

lightsout8502 · February 7, 2023

I am having this same issue. I have a 2022 At4 duramax. 1800 miles and Everytime my rear flexes I hear a nose on the driver side. I tried the spring thing and I still hearing noise. Anybody have anymore suggestions?

GMCustomerService · February 8, 2023

On 2/6/2023 at 9:24 PM, lightsout8502 said:

I am having this same issue. I have a 2022 At4 duramax. 1800 miles and Everytime my rear flexes I hear a nose on the driver side. I tried the spring thing and I still hearing noise. Anybody have anymore suggestions?

This is certainly not what we like to hear, lightsout8502. 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 2022 GMC Sierra AT4 Duramax. To do so, please send an email to [email protected] with ATTN: lightsout8502/GM Trucks in the subject line.

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