BurnsMax

Mine runs 26-28 driving unless I hard accelerate, then it jumps to about 60

I don't believe you can without and OBD2 reader. You can call onstar and have them give you the codes.

I don't have your particular truck but the update I got today was system update 135116. Here's a link about the update. https://static.nhtsa.gov/odi/tsbs/2020/MC-10174276-9999.pdf

No, they are not the same fluid. https://www.lubegard.com/the-year-of-the-10-speed/

Yes I can confirm it shuts down in park. I have an OBD2 reader and it shuts down when placed in park and then when it's placed in drive it will go back into the regen if it wasn't finished after a minute or two of driving.

A regen lasts 10-20 minutes depending on the driving conditions. There is no way to know it is in a regen unless you are using a OBD2 reader and app. The only time there would be something on the display is when there has been several unsuccessful regens. Then there is a message that comes up stating to keep driving. My guess it was in a regen. When you put the vehicle in park it will shut down the regen process. So that whistle will go away

It is usually once per tank of fuel. It varies on when it does it. It will do more often if it has been idling a lot or small short trips. Then it will do a regen every 100-200 miles

It could have been the truck was in a DPF regen when you were driving it. I get more of a whistle while the truck is going through the cycle.

Yes I have this happen, it is usually when I first get on the highway and it will shoot up to that temp for about a minute then back down to 210

I totally agree with what you are saying. I see what you mean. Here is a pic of mine IMG_4732.HEIC

Didn't even realize it until this post, but mine are the same. The stepping points for front and the rear are in the right position IMHO are in the right spot to step in and out of the truck. I see what I mean and this might drive me nuts now looking at it

Welcome to the forum and congratulations on your new truck. Read my post here, it has the TSB in it for your problem

I haven't had an issue with apple car play. Are you using a true apple cord or using an aftermarket one? I know in the past when using an aftermarket cord, I had issues with my laptop, etc.

https://pedalcommander.com

Probably not. Most automotive parts stores out where I'm at will do it free. Thats a better option than having multiple people in your vehicle at the dealership