Back in Black AT4

Hi there - 2020 AT4 6.2L Sierra owner here - every once in a while upon turning off my truck, I'll get a rapid horn honk burst similar to when you leave you keys in the truck...it's almost like it is trying to notify me of something...I had some DTC's stored in memory...I wonder if that is the cause and I should get them cleared by the dealer (or get a tool to do it myself)? Any other ideas?

I subscribed to it...I often forget to lock the doors for the night so I'll lock the truck from my phone while in bed. I've also used the navigation send-to-vehicle function a few times which is convenient sometimes while pre-planning for a trip. I agree that it is way too expensive for what you get...

Still no leak here on my 2020 AT4 (Feb 2020 build date) and I've been blasting it weekly with the pressure washer when washing the truck...

I was researching Duratrac's vs. KO's vs. Ridge Grappler's performance and the one thing that makes it mandatory to go with Duratrac's is snow performance! Living in Canada here and cannot have a poor snow performance tire!

Definitely prefer the look of the AT4 over a Denali...chrome is out of date now...

Yep all AT4's have the black headliner - looks sporty and more youthful to me compared to the grey headliner which is found everywhere...

I have a 2020 GMC AT4 6.2L with the GMPP (aka Borla Touring) Exhaust and CAI and if I was to do it again I would have not chose those factory options and buy a Borla S-Type catback afterwards. Don't get me wrong, the GMPP Exhaust has a nice rumble and louder than stock...it's just not aggressive enough (other than a cold start which sounds great!). The only thing I worry about with going with a S-Type is when I tow a trailer...that could be annoying on a longer drive...not sure. I often think about switching the GMPP muffler to an S-Type, but after doing some research, I discovered I would need to buy a Borla ATAK muffler and a S-Type muffler/resonator as that is essentially what the Borla S-Type actually is...it's a Borla ATAK system followed immediately by a S-Type muffler/resonator... to slightly mellow out ATAK muffler...I'm not sure if the GMPP/Touring pipe length would align with the ATAK+S-Type setup...even though the GMPP/Touring is much larger muffler than the short ATAK and S-Type mufflers...I would probably have to pay an exhaust shop cut the pipe and weld...not sure it would be worth the trouble/cost...would be nice if I could simply remove the GMPP muffler and direct swap in a ATAK muffler and S-Type resonator without any modification of the pipe length...

I've been thinking of changing the factory GM Performance Exhaust muffler only to a Borla ATAK or S-Type...has anyone swapped out just the muffler? Is it a direct swap or is there more pipe needed?

6'5" 360lbs. here and I can step in and out with good comfort...kinda worry about the seat cushion (closest to the door) durability sliding in and out...

Thanks a lot for the bulletin! My new AT4 set these codes immediately after start-up while at a drive-in movie with my family moving around in the truck bed...the truck probably detected the movement while in park...it all makes sense now... btw the check engine light went away after a few key cycles and the truck did not exhibit anything abnormal other than the indicator light. My dealer said not to bother coming in to clear the codes out of history.

My AT4 was produced in Feb 2020 @ Fort Wayne and no leaks so far even after directly spraying the window perimeter, sliding window and spoiler with a pressure washer during a couple occasions...

Just picked up my 2020 AT4 6.2L (with the off-road Duratrac tires and no tonneau cover) and I'm getting 14 L/100km (16.1 MPG) with a mix of driving types over 700kms. The way I view it, I bought the 6.2L because I wanted the performance...you have to pay to play...

Bought my new 2020 AT4 last month (July) and have given it a few washes with my pressure washer and really soaked the rear sliding window, perimeter and spoiler to see if I could detect any leak early on in the warranty period...no leaks whatsoever...feeling good...I wonder if they fixed the issue?

I have the GMPP exhaust and intake on a 6.2L and I like the sound like others are saying...loud-ish at start-up and acceleration but quiet cruising. I often think about possibly switching to the S-type for a bit more sound...but the wife and kids may not like it...

I wouldn't expect an issue as it is pretty high up, but as an additional protective measure I would fold down and wax the inner painted portions and put lithium grease on the hinges. I'm more worried about the truck frame rusting out than modern galvanized body panels.

Has anyone here had their 2019/2020 Sierra/Silverado sprayed with Krown oil yet? I know 100% on some other vehicles, Krown has swelled up weatherstripping, rubber gaskets and weather-pack connectors...but it can also depend on the model, the rubber being used and how the oil is applied. I haven't heard of any experiences yet with 2019/2020 Sierra/Silverado models so just wondering if there were any issues. I am 100% against rubberized undercoating as it traps in moisture and rots from the inside out...seen it many times...Krown oil on the other hand displaces moisture... The other downside of a Krown oiled car is that the underbody collects all the road dust and get very dirty...but dirty is better than a rusted-through frame...

They are just a series of fans in the seat bottom and seat back...the cooler the air source, the cooler the effect will be

Thanks! I didn't think about those items!

We're considering purchasing a Jayco Jay Feather 25RB travel trailer with a gross trailer weight of 7,000lbs. https://www.jayco.com/products/travel-trailers/2020-jay-feather/25rb/ Our 2020 AT4 6.2L has a tow rating of 9,200lbs., a GCWR of 15,000lbs. (which is key) and a as-spec'ed curb weight of 5,185lbs. The way I see this is (I'm new to this whole towing thing): 15,000lb. Gross Combined Weight Rating (GCWR) minus 7,000lb. Gross Trailer Weight minus 5,185lb. Curb Weight = 2,815lbs. remaining for passengers and equipment....is this correct? Anything else I should consider?

I just picked up my 6.2L AT4 last Friday...during the test drive (cold start) it ran and idled perfect but was near empty (factory gas)...when I picked it up on Friday the dealer put a half-tank of 87 octane gas and the truck had slight trouble maintaining an idle...felt like a slight miss in the engine and also showed in the tachometer...I sat there setting up the truck features for about 30 minutes idling with no improvement in idle quality...I drove around the corner to the nearest gas station which had 94 octane...filled the rest of the tank with 94 octane and then it idled perfectly...I wouldn't want to risk putting 87 octane again...I know that the knock sensor would ****** timing if it detected knock and reduce engine performance, but I'd rather pay a bit more for better fuel...probably go 91 next fill up though as 93/94 octane is expensive...

New to the forum - just purchased my brand new 2020 AT4 on Friday! - 6.2L V8 - Crew Cab, Short Bed - Performance Pkg. (435hp 469 lb-ft.) - Off-Road Pkg. (Mud-Terrain Duratracs) - Preferred Pkg. - Premium Pkg. - Technology Pkg. - Driver Alert I Pkg. - Driver Alert II Pkg. - Sunroof Clay-barred and polished on night #1 and waxed morning #3...so happy with this truck so far! Only problem was the dealer filling half the gas tank with 87 octane...when I went to start it with the salesman, the engine felt like it had a miss at idle and couldn't idle smoothly like it did during the test drive...salesman confirmed they used 87 octane...the 6.2L engine recommends 93 octane (I plan to run 91)...went to the nearby gas station and filled the remaining half-tank with 94 octane and the idle smoothed out and was back to normal...I also went to Canadian Tire and bought some STP octane booster to help the octane mixture a bit more...runs and idles great now! The salesman said I could run 87 octane but I call bull crap on that...it was having a hard time keeping an idle at 87 octane and wouldn't want it under load or I would imagine it would have detonation...