What's my question? Not sure, but am hoping someone can chime in on GM's max trailering package. I'm looking primarily at '17s/'18s, but maybe somebody could shed more light on the '19s/'20s as well?
The NHT option is the big tow package on the 1500 truck. It comes with a higher rated 4300 rawr which is good for around 1900 lb in the bed payload. For a 9k trailer you will want the 6.2 engine with 420 hp and 460 torque 3.73 gear with the 6 speed tranny. Newer models come with the 10 speed tranny.
Later model '14 and newer 1500 truck with the 5.3 are rated at 355 hp and 383 torque. Hands down more towing performance the the older 5.3 engines with the 4 speed autos.
I use the wifes '16 1500 chevy 4wd 5.3 with 3.42 gears 6 speed tranny pulling a 10k trailer with a blue tractor with 8640 up to 9460 lbs on the trailers axles depending on which implements I have on the tractor. Its mostly flat with a few hills. The 5.3 does a much better job than the old 5.3 but for a rv trailer this size going across country the 6.2 engine/10 speed tranny/NHT option is the way to go.
The 5.3 and 6.2 haven't changed any in the last 5-6 years. In those years GM has used the 6/8/10 speed tranny depending on year models.