Dusilligaf

I do not hear at idle at all, not even driving down the street, until its under load at about 1800-2000 rpm. If i let off the gas it goes away until i hit the gas again. After about a mile the noise is completely gone for the rest of my drive

I though it was an exhaust leak at first, i spoke to a GM tech and he said the same and to check the manifold bolts and flanges. But after thoroughly examining the bolts, they're all there and none broken, and i cant find any evidence of soot or blackening anywhere to show where it would be leaking from

does not sound like a pre ignition knock, I tried adding a video but the file is too big. i\I'll have to try and get another

My 2021 2500 HD Denali has 119k on it. I warm up the truck every morning for 5-8 minutes, drive it down the street all good and normal. Soon as I get it under load about 1800-2000 rpm up the hill it gets a hollow tapping noise from the driver side of the motor only while accelerating, its increase and decrease with RPM's. Does this for the next few accelerations for about a mile then goes away completely. If I shut the truck off and its sits 20 minutes 1/2 hour it will do it again for a mile or so and go away again. Once it goes away I can drive it all day and it doesn't make the noise anymore. Is it a lifter? I have done 2 oil changes since it started doing this, nothing has changed. My extended warranty just ran out and I don't know what direction to go in with this

2021 GMC crew cab 2500…Mystery noise. I couldn’t track it down, my mechanic can’t track it down, and he’s pretty thorough… It’s somewhere near or under the driver side…kind of sounds like going over a manhole cover, whithout going over one, or a quick rattle noise…mostly over light bumps Only does it when cold or not driven a while….then it goes away, comes back EVERY morning when I drive it to work, or if it sits a while does it for a short time and then goes away. It’s It driving me nuts. Any one had a similar issue, thoughts please….

Do you need to run higher octane fuel with it?

I was looking into the 3" zone lift for my 2021 Denali HD. I was hoping to use my stock wheels with 325-60r20 tires. Zone's website says I can use the stock rims and tires, but the clearance to their new control arms is tight, I don't know what the factory rim backset is, and if it will work with the larger tires on stock rims... Anyone have any thoughts or know what the backset is and if those bigger tires will work with that kit?

I was looking into the 3" zone lift for my 2021 Denali HD. I was hoping to use my stock wheels with 325-60r20 tires. Zone's website says I can use the stock rims and tires, but the clearance to their new control arms is tight, I don't know what the factory rime backset is, and if it will work with the larger tires on stock rims... Anyone have any thoughts or know what the backset is and if those bigger tires will work with that kit?

I believe there is a switch on the console in the diesel truck for grade braking that I do not have in the gas truck...

You have a gas motor, correct? And you notice it when driving it in normal mode, not just trailer mode?

I was used to coming on with or without trailer mode. it would actually say on the dash screen "grade braking active"... I dragged the brake pedal all the way down a steep hill in my new truck and got no message and no feel of the engine revving me up to slow down...but I wasn't in tow mode...ill guess ill have to try it that way?

So I traded in my 2015 1500 GMC Sierra, which had Max Trailer tow Pkg...it had grade braking....drove down a long steep hill with the brake on and it engaged, using the the engine and trans to slow down until you hit the gas and it it turned off.... I just picked up a new 2021 2500 Denali HD GAS....it does not seem to have it, which is surprising to me...unless I'm missing something, does it have to be in tow mode maybe?? Going from a 2015 SLT to a 2021 HD Denali I keep finding things that I miss from older truck that this new one doesn't do....

there is a guy that posted a video with a Denali black diamond, he put on 325-60 r-20 test drove it and had no rub, with stock ride on stock wheels

Yes, RC 2.5" lift and used the block in the rear...sits right the way it should