TripDad

I can confirm the duramax does not heat up much in -17F temps. Did not have my grill cover with me.

I had the recall done and I have a 1-2 mpg drop. I was averaging 18-20 now 17-18. towing my TT was getting 10-12 now 8-9. Brake squeal also. Not pleased.

in 90K+ miles in two different diesels i have had no issues with DEF or the particulate filter. Some people have. That said, since you are not towing heavy the gasser may be the way to go. Given you state the you do 100K/year the diesel may last longer. The 2500hd will generally ride better than the 1500 if you adjust your tire pressure for the load. As always, YMMV.

I have Toyo 295/65-20 AT3's on the stock 20's. Slight rub at full lock.

Supposedly, yes. As I understand it, the new controller can differentiate between magnetic and EOH systems.

We tow a 11K lb, 34' travel trailer, ~1300 lb tongue weight in Colorado. Pulls and stops great. Exhaust brake works well.

GM recommends using the trailer plug end from the same company that makes the truck side connector. There is a thread that discusses this in the Troubleshooting forum, if i remember correctly.

ITBS system is not quite ready for prime time. Taking my truck and camper to a RV tech to see if he can make it work. Trailer brakes connect intermittently. Some times I get the trailer brake gain not recalled.

I average ~18 mpg mix driving in Colorado.

I have been having brake controller issues since day 1. Two different trailers. Service advisor says ITBM is very sensitive and GM recommends using a Pollak brand 7 pin connector. I have one on order and will report back. Mean while I have the "Service Trailer Brake System" message now. Fun times.

That was my thought, thanks

IS there an actual suplementary spring? If so, where does it mount?

Just retrieved my 2020 AT4 2500HD from the local GMC service center. My trailer will connect, but then disconnects and reconnects intermittently. I was told everything is working as designed, and my problem is the LED lights. I did try the Curt product mentioned above to no avail. This is my second camper that this happened on. This truck is my first and last GM product. I am working on a workaround. If I am successful I will post back. Aside from this issue, and this is a big issue for me, I like the truck.

Hill descent control work on steep low traction environments often found off pavement. It is useful but also cumbersome at times. IMO, this is like most other driver aids, a more skilled, attentive drive likely will not need them often.

Over all the tech, camera, safety packages are very good to have. Worth is up to the individual. The AT4 does not come with adaptive cruise so forward collision alert is less effective. The HUD is a little weird at first, but very handy. I do not care for sunroofs, but that is what many truck get ordered with. Blind spot alert is just another useful tool. The cameras are great for many reasons. The HD camera rearview mirror is great at night. The seat buzzer i find is less annoying the chimes and bells. I am installing the (overly pricey) rear trailer camera on my camper to be able to better protect my stuff from the crappy Colorado drivers. None of these things replace driving well, just more tools to keep these very expensive truck looking good.