newdude

The door tag on the trucks takes in account all fluids and options as the truck is built but no occupants.

A zero options gas work truck. In all seriousness, a WT trim with no options is where you will find the highest payloads both gas and diesel. It won't be an LT, definitely not a High Country. If you can find some WT trucks on the ground at a dealer and check the door tag out, that would be the most definitive answer.

When GM sells the accessory mirror kit they give an authorization code to program the truck and any necessary modules. I don't know if GM supports programming without the kit aka you install takeoff tow mirrors. If they do, they charge about $200 for a VCI for the dealer to program.

On 2014-2018 Chevy trucks, Z71 was "technically" a trim level on LT and LTZ. You couldn't just get Z71 suspension option on an LT trim. 1LT was the regular 4x4, 2LT is a LT Z71. Same for LTZ. 1LT/1LTZ is chrome bumpers and regular 4x4, 2LT/2LZ is Z71, body colored bumpers, Z71 instrument cluster. GMC on the other hand, Z71 was just a mechanical option 2014-2018. So if OP has an LT Z71, he has a 6 speed. If he has an LTZ Z71, it could go either way 6 or 8 speed depending on engine option.

Are you 100% that you have an 8 speed then? What trim level is your truck?

What code(s) are stored in there? If you got a "service DPF" or some other emissions warning, there should be a code stored.

Pan-dem-ic. Its affected everything.

17 FT.LBS on existing cylinder heads. If installing on new cylinder heads, its a different spec.

DO NOT use Dexron VI. 8 Speeds use Mobil 1 LV HP ATF Synthetic with the BLUE LABEL. You will also need to follow the specific fill and level check procedures for the 8 speed as well as it has no dipstick/dipstick tube.

Rebates will be determined during the month in which you purchase. So if you order in December, but the truck comes February and you sign the papers, any rebates in February would apply. I wouldn't settle too hard on a final price as again, the rebates will vary.

What state do you live in? Is your concern that the AC light is on when it shouldn't be? The AC light being on is normal, the AC will only run based on temperature conditions but the light will still be on. Here is the operation for HVAC in a WT/Custom or any other trim with MANUAL climate controls:

GM and Ford joint ventured the 10 speed units. GM would use their 10L90 that's behind the Camaro ZL1 but with any truck related changes if they do it.

Sure it went to 3.42 but it gained 4 gears. 1st gear in the 10L1000 is 4.54:1 vs. 3.10:1 in the Allison 1000. The 10L/3.42 gear multiplication in 1st through 8th gears is higher than the Allison/3.73 combo is 1st through 5th. Could they put 3.73 in it? Sure. Would it be necessary? No. See 36,000lbs max tow rating. The 6.6 gas is the one that got neutered here. GM even got rid of the 3.73 on 2015-2019 trucks for a reason with the 6.0/6A. It was the better pairing. 2007-2014 trucks with 3.73 gears on average saw a 3500-4000lbs tow rating loss over the 4.10 trucks. GM went backwards on the 6.6 with 3.73 and 6A. Needs either to go back to 4.10 or they just man up and do the 10L90 and leave the 3.73. I still think that the joint venture had something to do with it that's why Ford got to do the gas with 10 speed HD trucks first.

Normal. The gauge kinda dummies at 210. Live data will show coolant temps on these gas Gen 5 engines in the 195-210 range depending on operating conditions.

There is a part# just no inventory. That is going to be your holdup.