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Posted (edited)
On 8/13/2021 at 12:30 PM, jayoco said:

Can you repost the picture of the location?  I'm having a heck of time locating this.  Thank you.

Sure. I'll put a link for a YouTube video I'll take tomorrow. That way you can see exactly where to look.

 

Edited by Firehawk99
Posted
On 8/5/2021 at 3:31 PM, Firehawk99 said:

Any trucks built after 3-4-21 should be fine. That is the break point.

What happened after that date? Did Chevy make some kind of change?  I am a few months away from getting my Silverado, but it's good to know what issues have been resolved and which ones are still pending.  Thanks. 

  • Like 1
Posted

Wait!  Don't buy an 8 speed under any circumstances, my 2021 is in the service department for the 3rd time. I have received no apologies or explanations from Chevrolet. I got a survey after about 2 weeks including a question about how it shifted. I answered ok. At 500 miles the issues started. Now at 5000 miles it is still acting up and GM could care less. They got their good review. The 8L90ansmission has been in production since 2014 and they still can't get it right. When will my valve train fail, your guess is as good as mine! The DFM has been in production since 2019 and still destroying one of the best V8 engines ever produced. Where is GM getting their engineers? Do I sound bitter? I am, my 1962 Impala SS with 327 V8 and aluminum Powerglide is more reliable than my new truck!

Posted
17 hours ago, dgstarr63 said:

Wait!  Don't buy an 8 speed under any circumstances, my 2021 is in the service department for the 3rd time. I have received no apologies or explanations from Chevrolet. 

Wasn't the issue the 10 speed transmission that Chevy was building along with Ford that was poorly designed and was eventually abandoned?

Posted
23 hours ago, dgstarr63 said:

No from the 10 speed I have in mine. And from what I’ve heard and read this 10 speed is one of the best tranny’s gm has ever put in the vehicle’s. Mine feels spot to me 99% of the time. My 8 speed in my last truck was decent too but I hptuned it to what I wanted the 10 speed is stock. 

Posted
On 8/5/2021 at 3:31 PM, Firehawk99 said:

Any trucks built after 3-4-21 should be fine. That is the break point.

That's what was said almost a year ago. Then it was post October 2020. Have a 2021 sierra 6.2 with the same issue as the original poster and mine has a build year build 12/20. And unfortunately it is the same exact situation and onstar was no help. Had to limp off the interstate, an uber for my family and I over to a rental agency and then meet the tow driver at the dealer to grab my stuff out of the vehicle and continue on my way to vacation.  I thought I paid 50 dollars a month for onstar to be my concierge. Instead I had to figure this all out myself while dealing with a new car with serious issues.   I lost all faith in my 70k truck and onstar.  

Posted (edited)

I still would like to find out what the exact problem was/is.  Be nice just to help understand the situation.  I have one of the trucks without the fuel management systems.  It was built in June 2021.  I would like to know if/how the parts are different.  According to one article I read my engine is exactly the same inside, but just has no method to turn on the fuel management systems.  Why would they even put the solenoids etc on it if they don't function.  Just curiosity getting to me.  I only have 1k miles on it.  Hopefully it keeps running without issues.  Been great so far.

Edited by milkmaster
Posted
On 8/12/2021 at 3:48 AM, Transient said:

Agreed.  Those who know how to turn a wrench understand stuff breaks and can be repaired.  People spend a bunch of money and demand perfection, but forget they spent a bunch of money because of inflation with a side of politics.  $60k yesterday got you a whole lot more than $60k does today. 

I agree with this to an extent, as I was a service manager for an AAMCO. However, the biggest issue I have with this particular issue is it has been known for about 1 year. GM has known about this and was either sending this truck out because there was a part supply issue , and valued profit over reliability or they have no clue why the lifters are collapsing. Either way, not good GM. 

Posted (edited)
3 hours ago, Philbert said:

That's what was said almost a year ago. Then it was post October 2020. Have a 2021 sierra 6.2 with the same issue as the original poster and mine has a build year build 12/20. And unfortunately it is the same exact situation and onstar was no help. Had to limp off the interstate, an uber for my family and I over to a rental agency and then meet the tow driver at the dealer to grab my stuff out of the vehicle and continue on my way to vacation.  I thought I paid 50 dollars a month for onstar to be my concierge. Instead I had to figure this all out myself while dealing with a new car with serious issues.   I lost all faith in my 70k truck and onstar.  

2 totally different problems here. The first was a bad batch of valve springs that were breaking causing the valve to possible drop into the cylinder. This latest one is a spring inside the lifter fails that allows it to collapse when the DFM is active.

 

Edited by Firehawk99
.
Posted
On 8/14/2021 at 5:50 PM, Firehawk99 said:

Here ya go.

 

 

I finally found it on the Denali and have two questions if you don't mind.   My sticker reads N1211341CU8X0083.

1. Where is the "N" factory?  I know the next few numbers are 1st shift, 2021, 134th day of the year.

2. What does the 1CU8X0083 mean?

 

Thanks again for all your help.

 

 

Posted (edited)
On 8/21/2021 at 3:44 PM, Philbert said:

That's what was said almost a year ago. Then it was post October 2020. Have a 2021 sierra 6.2 with the same issue as the original poster and mine has a build year build 12/20. And unfortunately it is the same exact situation and onstar was no help. Had to limp off the interstate, an uber for my family and I over to a rental agency and then meet the tow driver at the dealer to grab my stuff out of the vehicle and continue on my way to vacation.  I thought I paid 50 dollars a month for onstar to be my concierge. Instead I had to figure this all out myself while dealing with a new car with serious issues.   I lost all faith in my 70k truck and onstar.  

OnStar has NEVER been a concierge service.  $70k trucks still don't come with bidets.  People need to stop expecting it to clean their rears.  Finding out what you're actually paying for before you agree to it is a smart move.  Stuff happens.  Been there, done that.  I lose faith in people whenever they display a lack of basic intelligence via claiming the amount of money they spent on a vehicle should make it perfect, and that they didn't know what they were paying for.  I'll take a $70k truck over a $170k any day for 1 reason: The more expensive the vehicle the more problems they'll have and the more expensive they are to keep on the road.

Edited by Transient
  • Like 1
Posted
On 8/24/2021 at 1:49 PM, jayoco said:

 

I finally found it on the Denali and have two questions if you don't mind.   My sticker reads N1211341CU8X0083.

1. Where is the "N" factory?  I know the next few numbers are 1st shift, 2021, 134th day of the year.

2. What does the 1CU8X0083 mean?

 

Thanks again for all your help.

 

 

Are you sure the first letter is a N? It could be a M for Mexico. That is what my 2020 5.3 was.  The rest of it is just sequence #'s.

Posted
Just now, Firehawk99 said:

Are you sure the first letter is a N? It could be a M for Mexico. That is what my 2020 5.3 was.  The rest of it is just sequence #'s.

100% certain.  I've been under there 3 times now.  It's definitely an N.  I'd email GM but I have no idea who to email.  The only other plant that builds the engine is the Spring Hill, TN plant but I couldn't find their letter code.

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