Cant go passed nutral to get in reverse or park

I cant get the car to go past nutral I can put it in drive and
low and even manual shift and it shift threw the gears just
fine no slipping or any indication that it's the transmission
but I cant get the shifter to go past nutral when trying to put
the car in park I can get it to go past nutral if I open the little
cap next to the shifter and push the release button with a
screwdriver  any know what this may be or a way to track
down what the problem may be