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Do I have DFM model?

Tb21

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Didn’t know about afm/dfm issues before purchasing and would like some clarification on which model I have. Hearing about lifter failures around 5k miles. Only 1700 miles on mine so far no issues.

2021 LT Trailboss 5.3
No auto stop.
Manufacture date 9/21
 

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What I’ve found is auto stop and DFM are a package. Chip shortage is why some trucks came like yours. A friend of mine has the same as you. Wish mine was lacking a chip also 😉
 
You’re saying that I got lucky during the chip shortage and scored one of these without a AFM or DFM chip? At least from what you have heard?
 
If so that’s awesome. Got something good out of the shortages. Let’s go Brandon.
Since I’ve been driving it I’ve been trying to feel the 4 cylinder only and I can never tell a difference no matter how I drive guess that makes sense now. I kinda feel bad for the majority of people with the chip. AFM/DFM should have never been.
 
Okay so same question, I do have auto start/stop so I assumed I have dfm, but I can't tell a difference in my exhaust tone either. 21 Lt manufactured just before they pulled start/stop just can't verify date rn and I did a muffler delete fyi.
 
Forget about the mileage estimates for the lifter failures. Mine went at 32,400.
 
Didn’t know about afm/dfm issues before purchasing and would like some clarification on which model I have. Hearing about lifter failures around 5k miles. Only 1700 miles on mine so far no issues.

2021 LT Trailboss 5.3
No auto stop.
Manufacture date 9/21
Mine was built 8/31/21. I have DFM, but NO auto start/stop. I assume yours is the same. It would be nice if DFM was deactivated, but they still, from what I understand use the same lifters that fail inside the engine. They are ALL still subject to the failure, but there was a bad batch from Nov of 2020 through March of 2021 that have a KNOWN defect and fail sooner. Bottom line is we are all susceptible, but some more than others.

Wonder if GM changed the engine internals for '22 for those that don't have DFM???? Wonder if they finally got rid of the crappy lifters????
 
Guys you can always email socialmedia @ gm.com

Provide your Vin and ask for your build sheet - it will come with every RPO code and date built as well as plant. Mine was 2 pages long of RPO's
 
Guys you can always email socialmedia @ gm.com

Provide your Vin and ask for your build sheet - it will come with every RPO code and date built as well as plant. Mine was 2 pages long of RPO's
I tried that and they said they no longer provide build sheets.
 

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