FWIW, I flew AA (different airline, but - in theory - partners) PHL-MIA-GRU-MVD with the last segment on GOL last May. I could never get the GOL website to recognize their own PNR. I never called, but did try twitter. In the end, since it was just a short flight, I gave up and just got my boarding pass at the airport. Their board on here seems to indicate that, unless you buy from GOL, that you won't have much luck accessing your reservation via their site. Good luck!