Engine braking - seems almost too good

[studly]

My 2021 Suburban is my fourth generation of Suburban so I'm very familiar with how they drive in general.

The new 10-speed transmission was the best upgrade.  I am loving it -- especially for towing up hills where it is no longer "hunting" for the right gear -- going back and forth between a gear that races the motor and a gear that lugs the motor.

However, in some instances when letting off the gas, I noticed a decelerating effect that I had never experienced before.  I wasn't sure if I liked this or if it was supposed to do this.  I wondered if this would hurt gas mileage.  But, after a couple of tanks of gas, I'm finding that I'm getting about a full mile-per-gallon better than my last Suburban.

What convinced me that it is supposed to do this is when I tow downhill.  It is clearly using the engine to brake.  It works so well it almost seems too smart.  Recently, I noticed that is able to measure the inclination of the vehicle (i.e. the angle of going uphill or downhill). You can display the up/down and left/right angles on the dash.  Is it using this information to select the amount of engine braking?  Seems like it is. And, to me, that is pretty darn smart.