3309 is a synthetic blend correct that meets the T spec ? I use the Mobile synthetic ATF in my Cavalier it's been fine at 227,000 KM now. The Aveo because it does not shift in the the winter up here..I went to the Amsoil Multi-vehical ATF, ATF-1G and they tell me will not have any issues with meeting warranty requirements. My Cavalier is all Mobile and the Aveo is all Amsoil. Gm wanted I think 13 bucks a liter for their 88900925 and it's not even a synthetic fluid.