Shifter Feels Stuck Between Park and Reverse on 2000 Nissan Altima

I am considering buying a 2000 Nissan Altima with 69,000 miles for $4500. When I test drove it, I started the car and while pushing the button and taking the car from park to reverse, I had to struggle with it a bit. Going from park to drive or other gears was ok. Do you think this is a transmission problem or could it be just a cable or something needs to be oiled up?

Asked by for the 2000 Nissan Altima
Have 'shift-lock' mechanism tested. Any trouble getting it back in park and removing the key?
Thanks for the reply. No I don't remember having a problem getting back in park and removing the key.
a bad brake pedal sensor will make the car not shift from park into gear