Chev. Motorhome with 400 transmission will not stop in the park position, it will roll as if in nuetral. It will stop if vehicle is facing uphill and you kill engine, but not true for facing downhill.
RV is a 1996 Airstream "cutter" motor coach. Just wont lock into the park position. And with so few miles on it, what could be wrong if not the linkage?