2023 AT4X Muffler Delete gone wrong

[AT4XMAN]

Hi All, I took my new truck to the local exhaust shop for a simple resonator delete like Ive done on my past 5 GMC V8 trucks. Well, I got the rig back and something is wrong. Exhaust note goes from very loud to completely silent while driving, also making crazy helicopter type noise at low RPM. Not sure what went wrong...any ideas?

 

AT4 Forum Fav 👍

TORQUE Airbag Suspension Kit for 2019-2024 GMC 1500 - Grab one through Amazon!

[gemarsh]

Hi All, I took my new truck to the local exhaust shop for a simple resonator delete like Ive done on my past 5 GMC V8 trucks. Well, I got the rig back and something is wrong. Exhaust note goes from very loud to completely silent while driving, also making crazy helicopter type noise at low RPM. Not sure what went wrong...any ideas?

Gas burner? Helo sound makes me think of cylinder deactivation.

ETA... try dropping it into L9 and see if your sound is still there.

 

[AT4XMAN]

Gas burner? Helo sound makes me think of cylinder deactivation.

ETA... try dropping it into L9 and see if your sound is still there.

Yes 6.2l. Appreciate the suggestion. Now…how does one “drop into L9”

 

[gemarsh]

Shift transmission shift lever to L. It's the notch below D. On shifter there is a up and down arrow push buttons. A person can, from neutral, push the up button and the gauge cluster will show L1, L2, L3, etc. It locks the tranny from shifting into any gear that is above what a person choses.

Or a person can manual shift the transmission up, kinda like a manual. No nothing like a manual but kinda. That makes a whole lot of sense, huh?

Dropping the shifter into the L mode, locks out the cylinder deactivation.

 

[usmcfiredog]

Shift transmission shift lever to L. It's the notch below D. On shifter there is a up and down arrow push buttons. A person can, from neutral, push the up button and the gauge cluster will show L1, L2, L3, etc. It locks the tranny from shifting into any gear that is above what a person choses.

Or a person can manual shift the transmission up, kinda like a manual. No nothing like a manual but kinda. That makes a whole lot of sense, huh?

Dropping the shifter into the L mode, locks out the cylinder deactivation.

Except if you go to L10 then it will be reactivated. You have to stay in L9 to not have deactivation

 

[Pb82 Ronin]

If its a 2023, there shouldn't be any cylinder deactivation occurring. GM removed that feature in 22 and later models. OP, can you post a video of ir?

 

[usmcfiredog]

If its a 2023, there shouldn't be any cylinder deactivation occurring. GM removed that feature in 22 and later models. OP, can you post a video of ir?

That is not true. 2022 Refresh and later does have DFM again. It was only for a short period of time where they stopped having DFM and the auto start stop. I could be mistaken, but then again I don't remember them producing engines without DFM but they could have but it would have been for a short time period like the Auto Start Stop "Feature"

My 23 AT4X definitely does have DFM and you can tell as you come up to a stop light.

 

[Brocky]

I have a 22 refresh with the 6.2L. I have done a muffler (and flapper) delete and yes, it is VERY “throaty/loud” on start up and then quiets down. And yes, it also has DFM which will make it almost go silent on approaching stop light and stop signs unless in L9. I find my exhaust a little loud in the cab when under load or pulling a trailer. I actually think I might need to add an aftermarket muffler to help reduce the cab noise. If anyone else has done this, please let me know and what muffler you went with. Hope this helps, Thanks in advance.

 

[Pb82 Ronin]

Fair enough. I guess I'm one of the lucky ones without DFM then.

 

[FirstTimeTruckOwner]

I have a 22 refresh with the 6.2L. I have done a muffler (and flapper) delete and yes, it is VERY “throaty/loud” on start up and then quiets down. And yes, it also has DFM which will make it almost go silent on approaching stop light and stop signs unless in L9. I find my exhaust a little loud in the cab when under load or pulling a trailer. I actually think I might need to add an aftermarket muffler to help reduce the cab noise. If anyone else has done this, please let me know and what muffler you went with. Hope this helps, Thanks in advance.

Hey Brocky - I just did the muffler delete on my 23 AT4X and agree that the in cabin noise/drone is almost unbearable. What did you end up doing to yours? Did you add a muffler or resonator in?

 

[Pingbling23]

Hey Brocky - I just did the muffler delete on my 23 AT4X and agree that the in cabin noise/drone is almost unbearable. What did you end up doing to yours? Did you add a muffler or resonator in?

Did you just delete the muffler or the 2 rear resonators also? Videos make the muffler delete seem just right and not to loud but I don’t want drone and that seems to be a common complaint with the muffler delete.

 

[FirstTimeTruckOwner]

Did you just delete the muffler or the 2 rear resonators also? Videos make the muffler delete seem just right and not to loud but I don’t want drone and that seems to be a common complaint with the muffler delete.

I left the resonators and removed just the muffler. I even left the flapper in...

 

[Pingbling23]

I left the resonators and removed just the muffler. I even left the flapper in...

I’m surprised it would be that loud. Seems like the muffler delete is on the quieter side of the borla s and much quieter then the atak. Why did you choose to leave the flapper in? A lot of videos I’ve watched said to remove it because it will cause unwanted rattling.

 

[FirstTimeTruckOwner]

I’m surprised it would be that loud. Seems like the muffler delete is on the quieter side of the borla s and much quieter then the atak. Why did you choose to leave the flapper in? A lot of videos I’ve watched said to remove it because it will cause unwanted rattling.

Because I didn't want any drone...much good that did me...

I'm going to give it a few weeks and if I don't like it, I'll take it to a shop and get the stock muffler welded back in.

 

[Brocky]

Hey Brocky - I just did the muffler delete on my 23 AT4X and agree that the in cabin noise/drone is almost unbearable. What did you end up doing to yours? Did you add a muffler or resonator in?

I have been living with it still to this day. I think I want to either put on an Atak muffler or something similar. I really want a nice sound but would love to find something to cut down on the cabin noise/drone. If anyone else has done something similar it would be great to know. Thanks in advance.