trany problems

I have a 98 mustang gt auto and for some reasone when it gets cold it is extremely hard to get the car out of park, I have to push on the button on the shifter handle to get in out of park. I was wondering if anybody knows what is going on, I have installed a new handle so i am wondering if it is the shifter cable?

I mean that when you try to push the botton on the shift handle it is hard to even get it to push in to release the shifter and get it out of park.