Shift points (automatic transmission - shifts seem late)

[Thymeclock]

This thread is relevant as it explains why the shift points are delayed: http://www.aveoforum.com/forum/f106/...ity-mpg-10086/

BTW, it isn't the design of the Aisin transmission that's at fault. The problem lies in the way GM programmed the electronic transmission control module.

[petrified.rabbit]

The problem lies in the way GM programmed the electronic transmission control module.

did you see that trifecta has successfully reprogrammed the transmission in the automatic cruze? now if i could just verify which it is.. if they could do it for the aveo.

[Thymeclock]

did you see that trifecta has successfully reprogrammed the transmission in the automatic cruze? now if i could just verify which it is.. if they could do it for the aveo.

I sure wish they would! I have a sneaking suspicion that the transmission programming may be the same for more than one model that Chevy makes. When the dealer was checking out my Aveo for my transmission complaint, they gave me an HHR to drive as a loaner car. I swear that the transmission in that shifted at the same (late) points as my Aveo. (I hated that HHR and was very glad to get the Aveo back.)

[noking]

Man, that thread Thymeclock referred to is right on! Those of us who have much time behind the wheel on various automobiles just naturally pick upon design flaws such as this. Makes one wonder who programmed it this way and why. Coming up with an improved 'chip', or TCM will not be a priority for any one concerned, so we'd better not hold our breath. As for as a consortium of owners pressing for action......I'll sign on! I'm coming away from this post with much more pertinent information.......thanks you.

[MetroMPG]

Makes one wonder who programmed it this way and why.

"Consumer acceptance" is the usual reason. (Driveability would be the reason, I would guess.)

Make an automatic upshift "early" and GM would end up with 100% of auto reviewers (and some owners) complaining about the lack of power in the upper gears and the frequent downshifts needed to accelerate hard.

A "Power/Economy" button/programming would have solved the problem though.

[Thymeclock]

"Consumer acceptance" is the usual reason. (Driveability would be the reason, I would guess.)

Make an automatic upshift "early" and GM would end up with 100% of auto reviewers (and some owners) complaining about the lack of power in the upper gears and the frequent downshifts needed to accelerate hard.

Absolutely. If the car were geared for economy, most American drivers would say that the car can't get out of its own way.

A "Power/Economy" button/programming would have solved the problem though.

I have that option on my old Galant. But that car has more than enough power even in economy mode, so I never need to activate the 'power' button.

I am wondering about those tuner companies that do modifications to alter the shift points, however. I assume that their goal is to raise the shift points so that the car will have more power. But some of us want to lower the shift points so we can get better fuel economy. Would their programming mods make the latter possible?

[petrified.rabbit]

I am wondering about those tuner companies that do modifications to alter the shift points, however. I assume that their goal is to raise the shift points so that the car will have more power. But some of us want to lower the shift points so we can get better fuel economy. Would their programming mods make the latter possible?

if its at the point of tuning, ie vince from trifecta is doing it, and your not just installing a flash he has written on another aveo, then you could put and then test the shift points anywhere..