welcome, I also got stuck with the auto (2007 hatch), you would think the transmission would be amazing because it is the only part on the aveo that is made in japan but it has to be the worst. I think you are talking about it going into overdrive (a 5th gear of a sort). I use the hold button (shifts it into 3rd gear) when I have to speed up on the highway, then press it again to shift to 4th and then to overdrive. No real mods though, what kind of mpg's are you getting?