the problem is the cheapo white plastic piece is broken inside the shifter tube.
it's all one piece and cannot be replaced. you either need to buy a whole new shifter assembly from the dealer to the tune of around $150, or buy some chinese food, and make sure to get the chopsticks. after your satisfying meal, whittle a chopstick into a piece the same length as the plastic piece you removed, then stick it in the shifter tube. Make sure one end is whittled so that it actuates on the handle mechanism.
theres a detailed write up on JeepForum, with pictures and such.
Can't shift into Park or 1st Gear - JeepForum.com