01 Yukon Xl Auxilary Fuel Tank

[BKfirefighter3221]

My 2001 Yukon XL K2500 has a 15 gallon auxilary fuel tank behind the axle. I've been told this is a rare option. Well, the rear tank started leaking around the fill neck where it is sealed to the tank body. I called the dealer and it is discontinued and they tell me there are none in the country. I took it to a fuel system specialty shop which does plastic weld these tanks. They say because of where the leak is it is not repairable. I've called several "salvage" yards and they all say they can not get one.... What am I supposed to do?? There is a pump module in the auxilary tank and a fill hose that transfers fuel to the main tank. Can I possibly hook the filler neck directly to the main tank? I would then have to block the auxilary pump lines off as to not get a leak or evap. emissions leak code.