Shift points (automatic transmission - shifts seem late)

[noking]

My wife drives a 2005 Aveo, hatch, 4 speed auto, which we've had for a couple yrs. When I get to drive it, one thing I notice is while driving casually, I want to say "shift,,shift!". It seems to shift always as if you are bearing down the highway, shifting only after the rpm's are 2500 or more, and the last 'shift' or lockup is at 46 mph. I would think each shift would be quicker with casual driving; is there an improved 'chip' for the ECM or any other remedy, or am I just being too picky? It would get better gas mileage I'm sure at a better, quicker, shift routine. Thanks, by the why I just found the forum, very nice! Ron

[thehunterooo]

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?

[noking]

Thanks for the reply. Yes, we like the car & ours does rather well @ +30 mpg around town. But it seems 2nd & 3rd gear are delayed to shift also. I guess the difference in driving is we rarely get into fast traffic, mostly county roads, state hiways, and town streets. Sometimes I see a couple drops of motor oil on the concrete floor of the garage but I have've not found the source of the leak yet, it's not the oil filter. Ron

[thehunterooo]

how many miles do you have?

[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.

[thehunterooo]

honda has good transmissions...that hurt to say

[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.