Kuan, yes the tank is very well protected and is nearly indestructible since it's certified for military use. I think that I may be the first and only person to have broken the tank.

How it happened: I decided that I needed an adventure, so my wife and I joined Harold P for a week traveling remote locations in Baja. We were traveling to Bahia de Los Angles and were on the Camino Real trail, I was momentarily distracted when two wild cows ran across the road (that's my story and I'm sticking to it) and struck a rock. The rock caught the second metal strap that supports the fuel tank, the strap is anchored on the out-bound side, the in-bound side however hangs on a support rail. The strap slid back until it reached the end of the support rail, it then was forced up into the tank. It caused a cut approximately 3 inches long and 1/4 inch wide.
I exited the car and saw my precious fuel running into the sand. I definitely felt like I had been kicked in the stomach.

I will post a full trip report when I complete it.

I looked in my "Introduction to Service" manual last night and found a note regarding RR of the fuel tank. It stated that the body needs to raised slightly and the frame lowered slightly to do this, so it's not a DIY job. I will be taking the ML to the shop once my new tank arrives. This was an expensive lesson on the importance of not taking your eyes off the road.

Todd