1990 Pontiac Grand Am transmission stick is super hot

i bought the car.maybe a week ago car cut off in traffic with a rumble i restartd it engine started. when i put in gear it cut off . after i seem to let it cool off about 20 mintutes it started went in gear then cut off i checked transmission . stick it was super hot fluids were really thin and bubbley. is my transmission gone ? when i first drive it works fine after it warms up the car shuts off. can you please. advise me,

thank you, Richard W