I can say I have been very happy with the durability of the aluminum tank on my TM. I am not exactly sure on the age of the tank but I am sure it is at least 12 years old . I have only had one problem and it was 7 small holes in the bottom of the tank that had to be welded. The holes were not caused by rot, they were caused because the starter for the engine (mounted on the top of the tank) was not grounded properly and was grounding through the tank. The welder who fixed it was an instructor at a welding Tech school for 15 years and said he had seen this type of pitting before from electrical arcing. Even a very small "pit" caused by an electrical arc can quickly turn into a hole. The welder explained it as the arc starting a type of "chemical" reaction with the aluminum. The arc not only physically removes a small amount of aluminum but allows a chemical reaction starting decay at that spot. I ran a 4 ga dedicated ground from the engine block next to the starter to the frame of the truck and have not had any problems since.