Congrats - I picked up a holdover 2018 ZR2 2.8 in January. Liked some of the extra bits on the GMC Denali but liked the ZR2 look better. My truck had 2,000 miles (sales manager was driving it) on it and I've only put about 2500 miles on it. The 18's don't have a DEF percentage indicator until it's something like 75% and in 2500 miles I haven't seen a reading yet. I believe it's something like 5-7k that it'll need it though.

From most of what I've read, your best bet is just go to a truck service station that sells DEF at the pump and fill up from there as it's going to be the freshest (if it's a busy truck stop). The stuff does have a shelf life and it's not all that long. The emissions crap is the weak point on these trucks and most modern diesels.

If you're in a cold climate, read up on demuslifiers vs emulsifiers (anti-gels). You DO NOT want to use emulsifiers (ie: power service, etc.). I use Standayne in this 2.8 and my 5.9 cummins.

https://www.amazon.com/STANADYNE-DI...984574&s=automotive&sr=1-7-spell

It's also recommended to use some sort of fuel lubricant. Opti-lube XPD comes highly recommended.

https://www.amazon.com/Opti-Lube-XPD-Diesel-Fuel-Improver/dp/B00FOSSQJU

If you're on face book, join the 2.8 forums.

Good Luck & Enjoy