I installed a 2nd fuel tank on my 2001 IHC 4900 truck. How are the 2 tanks connected together? Do the pickup tubes from both tanks get plumbed together? Can also join both tanks with a crossover line from each tank drain.
Cross over lines are illegal. Your two tanks need to be the same size. You will need to have equal draw and return line routing and lengths to each tank with a "T" fitting connecting each.