When it works it slides in like butter but when it doesn't it feels like is hitting something to prevent it from going forward. I have never tried this but I am assuming that a GP will not let you shift from drive to Reverse or Park unless your foot is on the break to prevent damage to the transmission. This is just me thinking out loud. I will have to play closer attention to the shifter button also to see if it can be pressed in when I am experiencing this problem. I can't remember if that was a problem or not.
