Looking at it from the side the shifter arm is on the arm (or shaft) will have to be turned all the way clockwise to be in park. An automatic trans will turn in any gear but park so if it's out of the vehicle grab the output shaft with a channel lock pliers and see if it turns and if it's in the vehicle jack up the rear wheels and turn the driveshaft. When your turn the shifter all the way clockwise and turn the output/driveshaft it will click and lock up, which means it is in park.

Evan