I got an Aveo on May/05 - I have taken back to the dealer twice for transmission issues - the car doesn't shift on time between first & second - it just doesn't move. According with the dealer they're all like that -
DEALER"S SOLUTION - don't give gas at that moment, wait until shifts then you can accelarate.

MY CONCLUSION- I'm driving a car that at the moment that you need to avoid an accident it will get you into one!.

There are also other issues with this car - a month ago the car didn't start for 2 days - de dealer can't explain what happend.
The heat always goes to my face even when is set to the feet.

I spoke to GMC Customer Services, the dealer & there is nothing that they can do! What can I do??

Another dealer may be able to help.
MT

Is it still under warranty? If it is try other dealerships like MT2500 said, If not go to a reputable independent tranny shop. There should not be a delay in shifting.

Good luck