Car stalls in drive and reverse, but not in park or neutral. Auto Zone came up with a U100C code. What does this mean?

SOURCE: shifting from reverse to Drive

If your van has alot of miles, then just ignore it. Get a sevice done on it and let it warm up a bit and see if that helps the problem. When the miles get put on, especially with little maintaince, they have a hard time engaging "cold turkey". Another factor is that going from Rev to Drive(1st) you are going from energizing one accumulator to energizing two, and you're switching from the Rev clutch to the Underdrive clutch which tends to bleed off pressure the most.

SOURCE: chrysler concorde car wont shift from reverse to park

it sounds like your gearshift cable is broken..if you can jack up vehicle and support it safely,get someone to move shifter and look on driver's side of transmission and see if linkage is moving on trans..linkage is up near top of trans..i have seen this problem before

SOURCE: CHRYSLER VOYAGER 2.8CRD AUTO

1. A/T Fluid level empty or low
2. Oil pump of A/T Faulty
3. Selector lever disconnected
4. Torq converter faulty

SOURCE: Car acts like its in neutral when I put it into drive or reverse.

assuming you have checked the trans oil and it is full, it sounds like you need to take it to a good trans shop and have it looked at. it could be something simple or something major and expensive