What sifting problems that can be fixed without replacing transmission? on 2003 Chevrolet Impala

Sifting problems, when accelerating will jerk. Seems worse on inclines, on straight stretch will shift if I let off gas pedal, seems to be stuck in 3rd gear now. Also ABS & traction off lights are on & when starting the service traction system warning comes on. Changed transmission fluid & filter a week ago.

1 answer
Scan test of ALL modules needed! ......To be done by a mechanic....parts store cant do this....