Vehicle parked on boat launching ramp 25-30% slope concrete surface with 24 foot aluminum trailer in tow; boat off trailer, truck facing away from water, trailer closest to water. Sunny, ramp was damp, with some wood and aquatic vegetation on ramp. Vehicle was in 2 wheel drive. After unloading boat using a launch cord and pulling boat onto ramp, depressed brake and moved shifter from drive to park. Park engaged and stepped from vehicle when truck began to roll backward. Lunged into cab, saw shifter was now in neutral! was able to reach shifter and attempted to put into park. Gear shift moved to park but vehicle continued to roll and I heard an audible clicking from transmission area. Truck (and me) continued backward into lake, almost drowned but for help of a good samaritan on shore. When truck recovered it was in park, wrecker operator had to manually bypass this to load on flatbed. My prior 2019 Tundra crew cab did same thing I cannot believe this happened. In 2007 on your site someone reported same Tundra issue under controlled conditions. Something is wrong with this truck's transmission. Never happened under any other circumstances but I assure you it is going to result in someone dying I almost did. Both claims handled by usaa insurance, date of accident Monday, 5 Aug,

- Mechanicsburg, TN, USA