The truck when placed in park, and running will jump into drive after one minute or so. This has happened twice. The first time it happened, I got out to close a gate. The truck sat in park for approximately 2-3 minutes while I struggled to close the gate. When I got back to the truck, it made "pop" then shifted slightly. I looked down and it was in Drive. The second time it took it less time to shift to Drive from the Park position. Thank goodness we had passed in front of the truck and walked a hundred feet to the gate before it again made the "pop" and drove off without us, trailer in tow. It's lucky the wheel grabbed the side of the road and hit a tree 15 feet ahead. It could have been a very serious accident.