aztek shifter it not going into park or drive 1&2 on 2004 Pontiac Aztek

you can drive the car around and it feels like the internal button on the shifter is jumping up and down randomly. i went to put in park and when i got to reverse it was like i hit a wall and would not go in to park. i drove around the block and heard the noise from the shifter a few more times but now it when in to park. it has done this on a few occasions please any suggestions

Asked by for the 2004 Pontiac Aztek
have you had tranny serviced? get a diagnostic run.