You are definitely allowed to do it with JJ even if you had no status at all. In fact they even have a tool for it in their website (you must have checked-in your original flight before) but coming from an international connection, I would do it directly at check in at GRU. When you reach the landside on arrivals, turn to your left and you will find Latam check-in for re dispatch of luggage for domestic flights. If the line is too long (even for status members), you can always take a bet and walk to GRU T2 and use the domestic flights check-in there. be prepared for a 10 minutes walk.
Domestic check-ins at GRU shall be done no later than 40 minutes before the scheduled departure of your new flight.