The contact owns a 2014 Jeep Grand Cherokee. The contact stated that while in reverse and attempting to shift into the Park position, the vehicle rolled backward independently and crashed into a tree. The air bags did not deploy. No injuries were sustained. The vehicle was able to be driven. No police report was filed. As a result of the failure, the shifter needed to be moved upwards before being able to shift the gear in the park position. A few years later while coming to a slow stop to place the vehicle in park, the gear shifter failed to remain in park. The vehicle continued to roll forward causing the rear driver-side door to hit the barrier around a nearby mailbox. The air bags did not deploy. No injuries were sustained. The vehicle was able to be driven from the scene. No police report was filed. The contact related the failure to NHTSA Investigation ID Number: PE15-030 (Power Train). The vehicle was taken to the dealer where they were not able to diagnose the failure and confirmed that there were no recalls. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was 80,000.