Drip leak from a can like part in the exhaust which is under the right back seat

You're describing a normal operation. When the emissions system is working properly, the exhaust is so clean, you can suck on the tail pipe and live to tell about it. The exhaust gas is carbon dioxide and water vapor. Typically, you'll see the condensed water vapor dripping from the tail pipe. When it has already condensed inside the muffler or resonator, water left standing in it overnight promotes corrosion. To prevent that, they drill a tiny hole on the bottom, usually on the back side, for that water to drip out. You're less likely to see that right after a long run at highway speed as that gets the exhaust system hotter, then the water is still in vapor form leaving the tail pipe.

Check out this article for more information on exhaust systems:

https://www.2carpros.com/articles/how-exhaust-systems-work

I drive the same model truck, but a 2014. I just looked at it and found the drain holes. The one at the back of the muffler has my red arrow pointing to it in the first drawing. The blue arrow in the second drawing is pointing to the drain hole in the exhaust tip. It's about an inch from the rear of that pipe. Those pipes have a rounded edge where water could collect if it wasn't for those drain holes.