Hi, I just bought a 2007 G6 3.9L 6 speed manual. As mr.sandman said you have to shift to Reverse to get the key out then when the key is removed it locks the trans in Reverse. There is a cable and lever on the right side of the shifter down in the console, the previous owner had disconnected it to disable this feature. I re-attached it for now, at least until I understand why they disconnected it.
My OE shift knob has all the leather peeled from it, just plastic now. New OE knobs seem expensive, but havent found aftermarket shifters with a smooth 16mm bore. Has anyone seen them?