I find the full gas tank noise to be distracting. Someone posted in another thread that it sounds like a watermelon is rolling around the back, and that is an apt description.
The first time I heard it, I stopped the van, thinking either I had run into something or something had come loose in the back.
Fortunately, it happens only for a short time, until the tank is no longer full. It still catches my attention, though, after two months.
Regards,
Maugham