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Posted
3 hours ago, Transient said:

A squeaky belt has nothing do with AFM and DFM.  Shifting into L9 won't change it.  People who refer to that solution are not talking about the noise from the belt.  However, I don't think it's a DFM issue because it's only happening on startup, not while the engine is just idling.  You indicated you have success with putting the truck in L9 and the noise went away, so it may not be a belt issue for your vehicle.  I haven't had the issue where I needed to shift into L9, so that might explain why I didn't notice the noise in your video. 

 

I can't help with the clunk noise.  Could be a number of things, none of which I've experienced in my truck, and my truck is parked on an 8% grade, nose down, nightly. 

 

Not only did my belt use to squeak on a cold startup, but also when the engine turned back on while driving after turning off at a red light.  Initial repair by dealer was to apply some sort of dry lubricant.  It reduced the squeak, but didn't eliminate it.  After awhile one edge of the belt wore enough that the squeaking went away.  Wearing is indicated on the edge, but isn't severe enough for me to be concerned about breaking.  Obviously a pulley is slightly out of alignment with the others, but the belt could be a smidge too wide, too.

That’s good info about the belt as I’m thinking I have that issue as well on cold startup, and instantly going to drive/reverse. I thought about spraying a little belt dressing on it to see if it gets better or worse. 
 

I think the noise from the video, and the noise at startup aren’t associated with one another. I’ve seen a handful of people with these trucks having literally the exact same complaints as me with no real resolution. I’m not sure if they’re just driving it in manual mode (like I am) and checking/waiting on a response from GM, or if they’re getting rid of them. A few videos I’ve seen swear that the noise is coming from *something* to do with DFM. I’m inclined to believe that since apparently switching to manual mode doesn’t allow DFM to operate at all. I really wish I could talk to an engineer that knew what happens when DFM isn’t on vs when it is. I’m sure they know about this, so maybe that wouldn’t do any good either. Just sucks I finally got the truck I wanted, and am met with instant issues that GM can’t figure out. 

Posted
34 minutes ago, JoshRM said:

That’s good info about the belt as I’m thinking I have that issue as well on cold startup, and instantly going to drive/reverse. I thought about spraying a little belt dressing on it to see if it gets better or worse. 
 

I think the noise from the video, and the noise at startup aren’t associated with one another. I’ve seen a handful of people with these trucks having literally the exact same complaints as me with no real resolution. I’m not sure if they’re just driving it in manual mode (like I am) and checking/waiting on a response from GM, or if they’re getting rid of them. A few videos I’ve seen swear that the noise is coming from *something* to do with DFM. I’m inclined to believe that since apparently switching to manual mode doesn’t allow DFM to operate at all. I really wish I could talk to an engineer that knew what happens when DFM isn’t on vs when it is. I’m sure they know about this, so maybe that wouldn’t do any good either. Just sucks I finally got the truck I wanted, and am met with instant issues that GM can’t figure out. 

I hear you.  If you've seen the thread about the reverse camera being of angle then you've seen the updates I've been providing to that.  Hint: As of about an hour ago we have a solution for it. 

Posted
22 hours ago, JoshRM said:

That’s good info about the belt as I’m thinking I have that issue as well on cold startup, and instantly going to drive/reverse. I thought about spraying a little belt dressing on it to see if it gets better or worse. 
 

I think the noise from the video, and the noise at startup aren’t associated with one another. I’ve seen a handful of people with these trucks having literally the exact same complaints as me with no real resolution. I’m not sure if they’re just driving it in manual mode (like I am) and checking/waiting on a response from GM, or if they’re getting rid of them. A few videos I’ve seen swear that the noise is coming from *something* to do with DFM. I’m inclined to believe that since apparently switching to manual mode doesn’t allow DFM to operate at all. I really wish I could talk to an engineer that knew what happens when DFM isn’t on vs when it is. I’m sure they know about this, so maybe that wouldn’t do any good either. Just sucks I finally got the truck I wanted, and am met with instant issues that GM can’t figure out. 

I am one of those that has had the issue and continues to look here for a solution, but i dont feel like there will be one at this point.  I have learned to just live with it, but when i roll the windows down on a nice day i put it in L9.  I believe others purchase the Pulsar LT module and I think that solves it as well.  Ive considered going that route but the $500 is steep, being that I have no other real interest in the other features it has.

 

You might be right on the noise at startup vs the noise when downshifting when coming to a stop being different issues.  I hadn't really considered that.  By the way mine only has the metallic chirp, not the clunking.  

Posted (edited)
2 hours ago, American Cobra said:

I am one of those that has had the issue and continues to look here for a solution, but i dont feel like there will be one at this point.  I have learned to just live with it, but when i roll the windows down on a nice day i put it in L9.  I believe others purchase the Pulsar LT module and I think that solves it as well.  Ive considered going that route but the $500 is steep, being that I have no other real interest in the other features it has.

 

You might be right on the noise at startup vs the noise when downshifting when coming to a stop being different issues.  I hadn't really considered that.  By the way mine only has the metallic chirp, not the clunking.  

I say clunk, but I think what I’m hearing wouldn’t be prominent if it weren’t for the chirp. So that may be nothing, honestly. 
 

It’s just a shame that people have to live with this, but it is what it is. I’m following a guy on YouTube that’s taken a legal stance, and has videos of startups and even attached a GoPro under his truck as he drove around and you could very clearly hear the noise we’ve come to know. He said he’s sending them to his legal team so I’m very interested to see how it works out for him. I really, really don’t want to get into all of that if I don’t have to. Best case scenario is they find a fix, and I can post it here so we can all get it resolved. Not hopeful on that, though. They’re telling him the same thing they’re telling us: It’s normal. 

Edited by JoshRM
  • 4 months later...
Posted

I've had this noise in both my 20' and 21' AT4 6.2's.  I can say it varies, in my 20' I only ever heard it at cold startup and restarting from the autostop for a bit.    In my 21' I also hear it when downshifting, and it seems like it's getting louder/lasting longer over time.   It's also interesting that you don't hear it in other 6.2 cars like the Camero I've heard, but I don't know what the real differences in those two engine systems are.  

 

It's a good thing I can turn off the autostop because when it restarts from a light it sounds like it belongs in a junk yard for about 5 seconds.  Bad enough it sounds like a rattle trap for 30 seconds when I first start it after it's sat for awhile.  I'd say GM should be ashamed but considering the lifters and rear window leaks they probably feel this is low on the priority list! 🤣

  • 4 weeks later...
Posted

I have a 2022 Chevy trail boss LT, and the thing squeals like a pig on a cold start up even when its +25 out side.. the truck only has 2,500 KM on it. Took it to the dealer twice and of course they don't here anything...  not sure if you han here the video.ATT00002.htm  

Posted
On 7/15/2022 at 11:56 AM, JoeyPottie said:

I have a 2022 Chevy trail boss LT, and the thing squeals like a pig on a cold start up even when its +25 out side.. the truck only has 2,500 KM on it. Took it to the dealer twice and of course they don't here anything...  not sure if you han here the video.ATT00002.htm  

This is certainly not what we like to hear, JoeyPottie.  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 Chevy Trailboss. To do so, please send an email to [email protected] with ATTN: JoeyPottie/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.
 
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
 

  • 1 month later...
Posted
On 7/22/2022 at 8:03 AM, GMCustomerService said:

This is certainly not what we like to hear, JoeyPottie.  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 Chevy Trailboss. To do so, please send an email to [email protected] with ATTN: JoeyPottie/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.
 
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
 

So, I took the truck in to the dealer and they said it was the exhaust making the ratel/squealing sound. they put a old exhaust on it that they had in there shop that had 130k on it and it still made the same sounds and GM will not replace it, so that tells me its not the exhaust. any way they had GM look into the problem and they came back and said, this is a normal noise and there is nothing they can do to fix the problem..... NOT HAPPY!! the service guy told my wife to put in a claim to GM and and ask for my money back and give back the truck... WOW!! GM also said that the noise is to make the truck sound like a V8, HAHAHAHA, Bull SH*T!! they also started 2 brand new high country V8 6.2L they had on the lot and they also made the same noise. to bad they didn't have a Chevy trail boss to show me . So now I'm stuck with this and no fix to the problem. this was the first time I ever bought a Chevy and will be the Last!! GM should be ashamed of them self's... I could go on and on.....     

Posted

Took the truck in to the dealer last week and GM said this is a normal noise and they will not replace the exhaust.. NOT HAPPY!! the service manager told my wife to put in a clime to GM and ask for are money back and give back the truck.... WOW!! they also started up 2 brand new V8 6.2L  high countries they had on the lot and they also made the same noise, to bad they didn't have some trail bosses there to show me. they also aid they took my exhaust off and put an old one on that they had lying around the shop that had 120K on it and it still made the noise. GM also said the ratel/squealing sound is to make the truck sound more like a V8.... HAHAHAHAH, Bull Sh*t... any way I guess I'm stuck with this as GM will not do anything to fix it, you think that they sell over a million trucks per year and make billons they would do something for there costumers that spend any where from 50k to 80k on a truck.          

  • 7 months later...
Posted

I know this is an old thread, but I just wanted to say thank you.

 

I have a 2023 6.2 Tahoe HC with 2k miles on it with this same squeal at start up, when stopping, and when attempting to accelerate aggressively after cruising and a slow and moderate speed (passing).

 

It's loud with the windows down. Sad.

 

The noise was also present in a 2023 Escalade with 100 miles and another 2023 Tahoe Premier with 12 miles. All 6.2L engines.

 

The dealer says it is a normal sound from the exhaust when using DFM.

 

The noise is gone when driving in manual mode (L9). 

 

This truly sucks. I can't believe GM thinks this is acceptable on $92k truck. 

 

 

Posted

It is sad this has been going on for years with no fix.   The solution evidently is to only park or drive next to other 6.2 GM's so that you can share the embarrassment of the rattling/chirpping noise at start and downshift.    You'd be amazed how many looks of "is your truck supposed to make that noise?" I get from cars next to me when the truck auto-starts on nice days.   Neighbor has a new Ram and it's not without it's issues, but it sure sounds quiet when it starts with a much more deep exhaust note.  Meanwhile mine sounds like it has a bunch of loose parts rattling around when it starts. 

 

 

  • Like 1
  • 11 months later...
Posted

Check your horn bracket behind your grill they come loose very common an make the creek/ squeak when taking off from a stop or stopping 

Posted (edited)

This came up awhile ago on another thread, but here's the tech link from GM basically saying it's their design.  They are basically admitting some do it and some don't and it's not their problem. 

 

"Do not attempt to compare these sounds to similar vehicles as the noise may be different from one vehicle to another, which could lead to unnecessary repairs."

 

Their excuse is it's caused by retarding engine timing under certain situations like cold start, auto start/stop, and downshifting at lower speeds.   Which causes the chirping/squealing.  However, it's hard to believe it's unfixable when other identical vehicles do not exhibit the symptoms. 

 

https://gm-techlink.com/?p=17055

 

GM should be embarrassed. 

Edited by todd308
Posted
On 1/24/2022 at 11:19 PM, Transient said:

6.2s don't have AFM.  And many trucks may not have DFM either.  This is a 6.2.  Did GM finally build one that has DFM?  Only squeak I'm aware of on the 6.2 is the serpentine belt.  I listened to the video, but couldn't identify the sound that we're suppose to hear.  I have a 2020 Trail Boss LT with the 6.2.  The serpentine belt is the only squeak I had, and it did eventually go away on its own. 

 

  • General Motors Engines
  • GM 6.2 Liter V8 EcoTec3 L87 Engine
  • The 6.2L with DFM — the largest and most powerful gas V-8 in the segment — is SAE-certified at 420 horsepower (313 kW) and 460 lb-ft of torque (623 Nm) and is paired with a Hydra-Matic 10-speed automatic transmission.

    “The increased variability of Dynamic Fuel Management means the engine will operate more often with a reduced number of cylinders, which saves fuel across the board,”

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