Funny though that when the ECO light comes on (assuming you have that feature active), and if you are looking at your fuel consumption gauge, it seems to always come on when you are in a certain liters per 100 km range, and of course when the light comes on you can hear a different engine tone/sound i.e. the "drone".
Now if you manually place the transmission in 6th, the ECO light will never come on, however if you watch the fuel consumption gauge, you will still see the same fuel mileage range as when the ECO light was on & the transmission was shifting into OD, but you do not hear the same engine tone/sound i.e. the "drone"......and of course the shifting clunk tends to goes away.
Just my observations based on my driving habits.
