FWIW I've got that engine in my new Traverse with the 9 speed auto. It's a beautiful powertrain.
You should also have a spin-on filter, correct? We have a '21 Acadia Denali with the same power train. It has a spin-on.
Last summer we took it on a 1,236 mile road trip. We averaged 26.6 MPG over the entire trip...actual. Very happy with that. One of the tanks we had a good couple of hours of basically idling through a 2 track in “off-road” mode in AWD to reach
-PARTRIDGE FALLS- . Nothing too crazy, just narrow and bumpy with a couple wash-outs I had to straddle.
Here are the tank computed MPG with what the vehicle’s computer said in parenthesis.
Tank 1: 296 miles/11.429 gallons……25.9 MPG (28.4)
Tank 2: 373 miles/13.84 gallons……..26.9 MPG (28.1)
Tank 3: 241 miles/10.381 gallons……..23.2 MPG (24.0) (this is when we went off road)
Tank 4: 326 miles/10.758 gallons…….30.3 MPG (30.2) (this was on the way home. Filled up when we got home. Still had ½ tank left and was showing 330 miles till empty!).
Then just last weekend we used it to tow a couple ATV's (~3,000 lbs) and a full vehicle (us as well as two golden retrievers) ~400 miles round trip. In trailer/haul mode it uses AWD and really raises the shift points. It also runs higher RPM's on the highway. Oil temps, according to the gauge, were in the 220°-230° area in 90° ambient on the interstate. Typically they are under 200°. Tranny temps ran completely normal the whole trip.