Good Tip Art,

I have not seen this flotation problem happen in a truck, but I did see it happen to an ATV.

A co-worker of mine stopped his 4 wheeled ATV in a flowing river about 16" deep, and stepped off the bike to have his picture taken. As soon as his weight was off the ATV it started to drift downstream and we all had to scramble to secure it before it dropped into a much deeper adjacent pool.

Mike