91 cutlass calais, stalls when i put it in gear

[uummm]

so, my brother just bought this car today, drove the car home and it drove fine, then went to back it into the driveway and the car stalled, so it restarts fine in neutral or park, but as soon as you go to put it into any gear, foward or reverse, the car jumps and stalls like then transmission is loading the motor to the point it stalls, like its not releasing and letting the car idle. ive tried to search the forum with no luck on what it could be, for older cutlass' it says to unplug the tcc as it would take away the top gear, but i dont know if you can even unplug it on this car, and if you can where the harness is located. all i know is that the tcc is located inside the transmission where you have to remove the pan to get to it. so im wondering if you can unplug the tcc and test it or do you just have to replace it and pray thats whats wrong, also is there anything else that can cause the car to do this. the car only has 123000 miles on it, i dont know if that makes a differance or not. but any help is appreciated. thanks for checkin out my thread

[uummm]

*update* turns out he can put it into second gear and it seems to work, also he said after it cooled down, it worked like normal, dont know if its gonna happen again (im betting it prolly will) but it seems to be workin for now.