UPDATE- got the leak fixed without removing the tank- turned out that mechanic removed some of the aft bulkhead right behind tank in engine compartment and found the problem which was fixed using gas tank repair kit from NAPPA auto parts- Filled tank and so far so good- hope this is it- going to lakr to find out today- will advise- by the way, tank only has seams at front and fear- we used a camera on a snake to examine the inside to find the leak and saw one piece construction- it is a nice tank-James