Jump to content

Recommended Posts

Posted

As stated though, all the internals for DFM are still present. It is only missing the computer hardware/software side that would allow it to function. Non-DFM engines are still seeing failures.

Posted
On 1/7/2022 at 7:43 AM, Stifler said:

OK I will be the dummy... there are 21s with no DFM? or are you talking disabled with a tuner? How do you know if you have or dont have DFM?

GM built some 21's without DFM (turned on), it was reportedly due to the chip shortage.  Your Monroney window sticker calls it out.

Posted
On 1/7/2022 at 9:15 AM, Byrds8 said:

As stated though, all the internals for DFM are still present. It is only missing the computer hardware/software side that would allow it to function. Non-DFM engines are still seeing failures.

Got a link to such a report?  I have not seen any.

Posted

No, someone else in the forum told me the same thing. But I do understand why. They arent going to rebuild the entire engine and have different ones because of the chip shortage.

Posted
On 1/10/2022 at 4:43 PM, Byrds8 said:

No, someone else in the forum told me the same thing. But I do understand why. They arent going to rebuild the entire engine and have different ones because of the chip shortage.

I was referring to a link of a report of DFM lifter failures on the "non-DFM" engines.

Posted
10 hours ago, Kilgore Trout said:

I was referring to a link of a report of DFM lifter failures on the "non-DFM" engines.

Again, no someone else mentioned they were in the forums. I was just restating as said in my original mention of it. I cannot verify one way or the other. From a personal standpoint, mine has just under 2600 miles and I have had no issues with the engine at this time. Well, other than the cold start noise that goes away after 20-30 secs.

Posted (edited)

I know this is outside this threads range. Here it goes. In my almost 50 years of driving I’ve never had a lifter failure. Iv only had one engine go bad. I’ve had warning of engines getting worn out by getting noisy or using oil. Never suddenly just failing. Transmission either. There’s no warning anymore, boom done. Progress.

Edited by KARNUT
Posted (edited)
On 1/7/2022 at 11:15 AM, Byrds8 said:

As stated though, all the internals for DFM are still present. It is only missing the computer hardware/software side that would allow it to function. Non-DFM engines are still seeing failures.

 

No, someone else in the forum told me the same thing. 

 

We've sold a bunch, zero in the field factory DFM disabled failures that I can report.  SupremePizza said "yes" on the first page, I replied to him to give any recent examples, never responded.  

 

So as I see it, until there's one witnessed at a dealer from a tech and they posted somewhere online about it, or an owner reports it in the field, its zero on here so far.  

 

Lifter isn't deactivating so odds of failure go to near zero.  Is it possible still for one to fail without actuation?  Yes.  But again, super low odds.  Saw one in the 14-19 Facebook group who had a Range or was tuned out and had a lifter still go.  

Edited by newdude
  • Like 2
Posted
3 minutes ago, newdude said:

 

We've sold a bunch, zero in the field factory DFM disabled failures that I can report.  SupremePizza said "yes" on the first page, I replied to him to give any recent examples, never responded.  

 

So as I see it, until there's one witnessed at a dealer from a tech and they posted somewhere online about it, or an owner reports it in the field, its zero on here so far.  

 

Lifter isn't deactivating so odds of failure go to near zero.  Is it possible still for one to fail without actuation?  Yes.  But again, super low odds.  Saw one in the 14-19 Facebook group who had a Range or was tuned out and had a lifter still go.  

@newdude. So are you stating that it’s more of a DFM issue, bad lifter issue, both? Looks like you are a mechanics and my father has recently retired so no more free work shop space!!  😂🤷🏼🤦‍♂️

 

Im just asking because my stepdad bought his 2020 Sierra SLT, loves it but has put 40k miles on it in little over a year and he is thinking of trading it in. I converted him over to GM after Ford for years. I don’t want him to trade and then have to worry about lifter failure. He can get excellent money on his trade in now and upgrade to a Denali instead of a SLT for the money. 
I’ve  told him to wait another year and get the new refresh but who knows when will that appear on lots and will they still have issues. 

 

my 2019 and his 2020 have been flawless. Neighbor has 2020 LT and his has been great as well. My boss has 2020 LT no issues with his either or 8 speed tranny. 
 

thanks for any info. 

Posted (edited)
1 hour ago, TNTSilverado said:

@newdude. So are you stating that it’s more of a DFM issue, bad lifter issue, both? Looks like you are a mechanics and my father has recently retired so no more free work shop space!!  😂🤷🏼🤦‍♂️

 

Im just asking because my stepdad bought his 2020 Sierra SLT, loves it but has put 40k miles on it in little over a year and he is thinking of trading it in. I converted him over to GM after Ford for years. I don’t want him to trade and then have to worry about lifter failure. He can get excellent money on his trade in now and upgrade to a Denali instead of a SLT for the money. 
I’ve  told him to wait another year and get the new refresh but who knows when will that appear on lots and will they still have issues. 

 

my 2019 and his 2020 have been flawless. Neighbor has 2020 LT and his has been great as well. My boss has 2020 LT no issues with his either or 8 speed tranny. 
 

thanks for any info. 

 

 

DFM is just the name of the newest cylinder deactivation.  DFM and AFM are in the basics the same thing, difference is DFM has all 8 cylinders equipped with active lifters, AFM its only 4 cylinders.  DFM can also alter the number of cylinders in operation from all 8 to as little as 2, where AFM is the same 4 cylinders can deactivate, V8 or V4 mode.  Both systems use the same exact lifters.

 

The issue with both systems is the possibility of active lifter failure.  The internal spring and locking pin mechanism is the most common culprit.  Control solenoid failure is a possibility as well but not as common.  Oil aeration, a miss timing of the solenoid sending oil to collapse the locking pin, a miss timing  of the solenoid closing and taking oil away causing the lifter to lock back in prematurely, lifter sticking in the bore.  

 

Like all other oil operated systems in modern engines, clean oil and good oil pressure are a MUST in their operation.  I'd say a majority of the ones we've done all were on high oil drain interval vehicles, so over 6,000mi between oil changes, but I can't say that 100% a shorter drain interval would stop lifter failure.  I have no further data to support that.    

 

The most recent rash of lifter issues was a production issue.  GM had a known batch of bad lifters made from September 2020 to March 2021.  This is the reason for the latest bulletin on the 2020-2021 trucks.  

Edited by newdude
  • Thanks 1
Posted
3 hours ago, newdude said:

 

 

DFM is just the name of the newest cylinder deactivation.  DFM and AFM are in the basics the same thing, difference is DFM has all 8 cylinders equipped with active lifters, AFM its only 4 cylinders.  DFM can also alter the number of cylinders in operation from all 8 to as little as 2, where AFM is the same 4 cylinders can deactivate, V8 or V4 mode.  Both systems use the same exact lifters.

 

The issue with both systems is the possibility of active lifter failure.  The internal spring and locking pin mechanism is the most common culprit.  Control solenoid failure is a possibility as well but not as common.  Oil aeration, a miss timing of the solenoid sending oil to collapse the locking pin, a miss timing  of the solenoid closing and taking oil away causing the lifter to lock back in prematurely, lifter sticking in the bore.  

 

Like all other oil operated systems in modern engines, clean oil and good oil pressure are a MUST in their operation.  I'd say a majority of the ones we've done all were on high oil drain interval vehicles, so over 6,000mi between oil changes, but I can't say that 100% a shorter drain interval would stop lifter failure.  I have no further data to support that.    

 

The most recent rash of lifter issues was a production issue.  GM had a known batch of bad lifters made from September 2020 to March 2021.  This is the reason for the latest bulletin on the 2020-2021 trucks.  

So, give me some clarification here if you don’t mind. What I’ve read is that the problem has predominantly been with DFM engines, but you’re saying that they’re identical lifters on both engines.

So, on my 2019 Silverado Custom L82 5.3 AFM engine, manufactured in December 2019, that I may very well have a problem eventually as well? 

I’ve got just over 18,000 miles on it so far with no issues at all, the truck has been great and runs great - so far!

Thanks in advance!

Posted
5 hours ago, newdude said:

 

We've sold a bunch, zero in the field factory DFM disabled failures that I can report.  SupremePizza said "yes" on the first page, I replied to him to give any recent examples, never responded.  

 

So as I see it, until there's one witnessed at a dealer from a tech and they posted somewhere online about it, or an owner reports it in the field, its zero on here so far.  

 

Lifter isn't deactivating so odds of failure go to near zero.  Is it possible still for one to fail without actuation?  Yes.  But again, super low odds.  Saw one in the 14-19 Facebook group who had a Range or was tuned out and had a lifter still go.  

Works for me then. I thought about trading in mine just to get a black 2022 one but after I saw they all had DFM on It was a hard pass. Glad mine doesnt.

Posted
On 1/15/2022 at 12:01 PM, newdude said:

 

 

DFM is just the name of the newest cylinder deactivation.  DFM and AFM are in the basics the same thing, difference is DFM has all 8 cylinders equipped with active lifters, AFM its only 4 cylinders.  DFM can also alter the number of cylinders in operation from all 8 to as little as 2, where AFM is the same 4 cylinders can deactivate, V8 or V4 mode.  Both systems use the same exact lifters.

 

The issue with both systems is the possibility of active lifter failure.  The internal spring and locking pin mechanism is the most common culprit.  Control solenoid failure is a possibility as well but not as common.  Oil aeration, a miss timing of the solenoid sending oil to collapse the locking pin, a miss timing  of the solenoid closing and taking oil away causing the lifter to lock back in prematurely, lifter sticking in the bore.  

 

Like all other oil operated systems in modern engines, clean oil and good oil pressure are a MUST in their operation.  I'd say a majority of the ones we've done all were on high oil drain interval vehicles, so over 6,000mi between oil changes, but I can't say that 100% a shorter drain interval would stop lifter failure.  I have no further data to support that.    

 

The most recent rash of lifter issues was a production issue.  GM had a known batch of bad lifters made from September 2020 to March 2021.  This is the reason for the latest bulletin on the 2020-2021 trucks.  

Since I have a factory disabled 5.3 that makes me feel better. Previous was a 08 5.3 AFM that I traded at 100k that never had an issue.

Question on the bad batch of lifters. Are the Sept 2020 to March 2021 engine dates or vehicle completion dates?

Posted
3 hours ago, Nutmeg said:

Since I have a factory disabled 5.3 that makes me feel better. Previous was a 08 5.3 AFM that I traded at 100k that never had an issue.

Question on the bad batch of lifters. Are the Sept 2020 to March 2021 engine dates or vehicle completion dates?

I have also been curious about those dates being engine build dates vs truck build dates. I have a DFM factory disabled Sierra with a September 2021 build date. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Articles

  • Posts

    • So you're saying toss the baby out with the bathwater? @txab posted article was her take on how AI can be used to manipulate pricing as it already does and has been rebuked by the judiciasry in housing. How AI can be and is used to maximize refinery or even Amazon operations all of which are true but because she is who she is; that makes what she says about what is true, false? Is that something akin to Pre-justice aka prejudice?    Look, I'm first in line to approach all information with caution just because we live in a world where people like to lie about someone or something with such a straight face and in such volume that it makes digging to the truth wearisome. Meaning I understand the skepticisms but if I were to toss out everything a person is for a view they hold then my pool of people to draw wisdom from would be non-existent and I'd be forced to reinvent the wheel daily. Not practical.    "Be innocent as a dove but as cautious as a serpent."    Test each word. Every good lie is part truth or no one would believe it. Find the truth in it and reject what isn't.    On this one, AI is being used to do what has been done by hand for hundreds of years already but at such speed, the point of a computer, that it is more easily monetized. This one wasn't that hard a lift.    I wrote a few formulas in a Lotus 123 program decades ago, a series of linked Macros actually, that allowed a daily inventory to be turned into a running P&L and production plan. Something that took three departments a week to assemble now took the time it takes to input the 'daily changes' in inventory. Later that was ungraded to the more powerful Excel program an and integrated with bar code scanning, inventory to supply was done once per shift. It had a huge impact on production scheduling, Seamless interruption flexibility, inventory error reduction, raw materials cost effective utilization and scrap reduction. Huge improvement in the bottom line. I spent months on that and AI could have done it in minutes. So yes, it not only can be used, they would be foolish to not try. The legality, ethics and morality are not the domain of AI. Humans need to keep a reign on it. 
    • New to this forum.  Also looking to tune a 6L80 and trying to work out all the issues in my transmission swap.  I have a 6.2 diesel (1983) and have removed the TH-400 and about to put in a 6L80 with a TCM-2600 interface and don't have a clue what I doing after that.  Did you (Leatherneck/RAV3) get your slip resolved? I too hate to spend that kind of money on a tuner that hopefully I will not need too many times although from what steelerdude15 added about the HP Tuner being great for diagnostics would be a plus.  I am also from WNC but below you in Columbus.  Any helo would be greatly appreciated.  
    • Sounds like a smart reasonable person with common sense. Bill O’Riley never said he was just a journalist, by the way.
    • It's like saying Bill O'Reilly is "just" a journalist.         Lauren Fix, widely known as "The Car Coach," is a prominent automotive journalist, television personality, and self-identified conservative. She is a frequent contributor to right-leaning networks and platforms, offering commentary that intersects the automotive industry, consumer economics, and conservative political perspectives. [1, 2, 3] Media and Commentary Network Contributions: Fix serves as the National Automotive Correspondent for Newsmax and is a frequent guest on Fox News and Fox Business. Video Platforms: She has contributed to PragerU, where she has hosted videos critiquing government mandates on vehicles. [1, 2, 3] Core Positions Anti-EV Mandates & Fuel Policies: Fix regularly critiques government subsidies and mandates for electric vehicles (EVs), framing them as impractical and burdensome to the average consumer. She advocates for consumer choice and supports traditional internal combustion engine vehicles. [1, 2, 3] Economic Analysis: Her commentary often emphasizes the impacts of fuel prices, inflation, and federal regulations on drivers. [1, 2, 3] Political Alignment: On her public channels, she actively supports deregulation, "drill baby drill" energy policies, and the removal of government restrictions on auto sales and manufacturing. [1, 2] For analysis from Lauren Fix on how consumer automotive choices can align with political leanings:
    • Wouldn't swapping out the original AFM/DFM parts for a complete Delete Kit be the best route to go if one could afford to go that route?
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...