Hi all. Anyone else notice your AT4 kinda squeaky on warm up and a rough idle after a minute or two. My 22 has about 8500 miles on it.
Rough idle and squeaky
- Thread starter BB2022
- Start date
Duramaximus
Well-known member
Negative, and I'm just south of 16000 miles. Can you tell where the squeaks are coming from?
- Thread Starter
- #3
Not sure. Almost like a dry belt sound.
slythetove
Active member
Definitely not. LM2 here
Yes. My 22 AT4X does the same. I thought it was my Borla exhaust, maybe not.
Duramaximus
Well-known member
Please do.
Xtremespeed2102
New member
Same here. Sounds terrible, and definitely a belt. I have been meaning to vary the rpms and see if it changes accordingly. 2022 Refreshed AT4 6.2L
Last edited:
Andystoy AT4
Active member
It may be helpful to post engine problems ( ? ) under the engine categories: 5.3, 6.2. LM2 etc. rather than a broad post where no one is sure what engine we are asking about? 
Elin3
New member
I have that on mine, 21 6.2. I read on a GM forum that it’s been linked to the DFM. If you put your truck in L9 it deactivates the DFM and the squeak will go away.
L9?? Please explain
Elin3
New member
So on your gear shift, put it in L for low(Manual) and increase to L9(L7 if you have an 8 speed transmission). It won’t stop the chirping/squeak on initial start but it will get rid of the chirping/squeak on down shift and also it’ll deactivate the auto stop and DFM function. (It wont work if you put in L10)
Great! Thanks
