Transmission does not shift into P
Check for a loose shift cable at the shift lever and the transmission control lever.
Check the park pawl spring installation and the park lever spring installation. If installation is incorrect, install the spring correctly. Make sure that the park lever stop is not installed upside down. Check the distance between the park pawl shaft and park lever pin. If the distance is out of tolerance, adjust the distance with the park lever stop.
Shift cable broken or out of adjustment
Connection between shift cable and transmission or body is worn
Park mechanism defective