Thanks -- I found it earlier this evening via a Youtube video's reminder. Never had needed it before! On the 4.1 there a little plastic plug in the bezel just in front of the P on the shifter; the plug pries out easily and exposes the black override button.As a workaround, you should be able to move the shifter out of the PARK position by using the emergency interlock override.
Your profile does not include your location, but from your description the problem seems to be related to cooler temperatures. If you have seen the problem worsen as the temperatures have dropped, I think you may have a dirty/sticky solenoid.Mine's been getting harder to operate too, first thing in the morning. ....... will have to wait for a cold start in the future.