slow speed suspension clunking

im4snow2000 · April 30, 2021

7 hours ago, Dogdad said:

Sorry for a dumb question, but do you have to undo bolts to slip in this rubber piece? I just had the leaf springs replaced on my new 21 Sierra with 300 miles on it and still have the clunking noise. Looking today I see the inserts are indeed plastic on the new springs .

No. I simply jacked up the truck under the frame, to relieve all weight off the rear wheel. Once up, with the tire slightly off the ground, you can easily drive a screwdriver between the leaf springs near the leaf spring insert (on both ends of the leaf springs), and pry the springs apart, and slide the rubber in on top of the plastic leaf spring insert that is "secured" to the lower leaf spring. The rubber I bought on Amazon and was inexpensive. So far, so good for me....but it's only been a week.

im4snow2000 · April 30, 2021

8 minutes ago, im4snow2000 said:

No. I simply jacked up the truck under the frame, to relieve all weight off the rear wheel. Once up, with the tire slightly off the ground, you can easily drive a screwdriver between the leaf springs near the leaf spring insert (on both ends of the leaf springs), and pry the springs apart, and slide the rubber in on top of the plastic leaf spring insert that is "secured" to the lower leaf spring. The rubber I bought on Amazon and was inexpensive. So far, so good for me....but it's only been a week.

Here's pic of the rubber installed. Please excuse the dirt.

Of note, if you have someone shake the truck side to side with moderate effort, you can recreate the noise. With someone shaking the truck side to side, you can visually see the upper and lower leaf springs moving laterally against each other.....and the upper leaf spring rubbing against the lower leaf spring INSERT is where the noise seems to come from. Whatever material they use to make the leaf spring insert isn't compatible with the steel and/or paint on the upper leaf spring....in my opinion.

Nothing like buying a $50k truck and "fixing" it with $3 of rubber.

Edited April 30, 2021 by im4snow2000

Dogdad · May 5, 2021

Installed the “SPRING THING “ KIT. Works great. No more clunking sound. Spring-thing.com. Here’s a pic of them installed on my 21 Sierra . Spring-things.com

Paul 74 · May 9, 2021

On 3/21/2020 at 8:44 PM, Kchampagne said:

My clunking under the bed was diagnosed to be a defective leaf spring. Dealer is going to fix it under warranty. Do you have the diesel? Sometimes the def fluid can slosh around and make a thumping noise.

My dealer kept my 2021 Silverado 1500 with 3.0 Duramax a day and half just to say clunking sound was normal and coming from rear live axle which is total BS..Not sure what to do next. The clunking is driving me crazy and only does it when bed flexes on uneven surfaces.

Dogdad · May 9, 2021

1 hour ago, Paul 74 said:

My dealer kept my 2021 Silverado 1500 with 3.0 Duramax a day and half just to say clunking sound was normal and coming from rear live axle which is total BS..Not sure what to do next. The clunking is driving me crazy and only does it when bed flexes on uneven surfaces.

Get the rubber spring things.. it’s your leaf springs . Read the upper posts. These are rubber bushings that separates the two leafs making the sound. It’s a known widespread issue.

Edited May 9, 2021 by Dogdad

Tymbo1026 · May 21, 2021

I purchased a brand new 2021 z71 RST with 6 miles on it. Truck is less then a month old from its build completion date. After 200 light and easy miles it developed a clunking sound only going slow and only backing over minor uneven ground. 50 more miles and the clucking has progressed to all the time, driving fast corners, slow corners, stopping you name it, it clunks. Beyond upset that a 250 mile, less them a month old truck feels like it is falling apart faster then the 55k 2016 i traded in. haven't owned the truck for 2 weeks.

Tymbo1026 · May 21, 2021

I purchased a brand new 2021 z71 RST with 6 miles on it. Truck is less then a month old from its build completion date. After 200 light and easy miles it developed a clunking sound only going slow and only backing over minor uneven ground. 50 more miles and the clucking has progressed to all the time, driving fast corners, slow corners, stopping you name it, it clunks. Beyond upset that a 250 mile, less them a month old truck feels like it is falling apart faster then the 55k 2016 i traded in. haven't owned the truck for 2 weeks.

Rich4032518 · May 26, 2021

I bought a 2021 Silverado custom. I’m hearing the clunking noise from the mid to back of the truck. Almost like something is rolling around in the bed of the truck. I notice it more on uneven surfaces and in reverse. Really bad pulling into and backing out of my driveway. I took it to my dealer and left it for 7 days. They couldn’t find anything. I drove with the mechanic and pointed out the noise. He says it’s the suspension settling in. He says bring it back if it gets worse, nothing they can do at this point. It’s is a very annoying sound. I wouldn’t have bought this truck if I would’ve heard this on the test drive.

Dogdad · May 26, 2021

8 minutes ago, Rich4032518 said:

I bought a 2021 Silverado custom. I’m hearing the clunking noise from the mid to back of the truck. Almost like something is rolling around in the bed of the truck. I notice it more on uneven surfaces and in reverse. Really bad pulling into and backing out of my driveway. I took it to my dealer and left it for 7 days. They couldn’t find anything. I drove with the mechanic and pointed out the noise. He says it’s the suspension settling in. He says bring it back if it gets worse, nothing they can do at this point. It’s is a very annoying sound. I wouldn’t have bought this truck if I would’ve heard this on the test drive.

It’s the leaf springs.. their lpkastic grey bushings suck. Install the Spring things.. easy fix and solves it. Read my earlier posts.

Paul 74 · May 26, 2021

Definitely the leaf Springs. To prove to yourself spray some silicone oil in between rear of leaf Springs where the rubber gouments are. Will go completely away for week or so. I ordered the springy thing kit but haven't installed yet.

taze · June 8, 2021

Just picked up my 21 RST z71 last Friday. I didn't notice the noise until I was going in/out of driveways. I originally was blaming it on the fancy tailgate but shaking that didn't sound right. I'll probably have my service advisor take a look. Or I may just go for the spring things.

Does anybody have a service manual that can verify the ubolt torque specs?

808GMC · June 13, 2021

This is a nightmare. I just got the truck 5 days ago and noticed it at 70 miles on it CLUNK CLUNK. 50k+ truck I really don't want this truck anymore.

Dogdad · June 13, 2021

3 hours ago, 808GMC said:

This is a nightmare. I just got the truck 5 days ago and noticed it at 70 miles on it CLUNK CLUNK. 50k+ truck I really don't want this truck anymore.

Buy the Spring Things .. easy fix and solves the issue.