Ok This may not be my problem, I have a pair of visegrips on the drain hose already... here is some more history. when I got the truck the front tank was not working and the rear tank was returning to the front tank, so I started with the transfer valve and found the switch was bad, replaced it and now you can hear the valve switching and was working fine, I tested the valve by removing the return lines, put a hose onto each one into a bucket and while switching the return lines worked correctly. Prior to this and since this truck had been sitting awhile, I fixed a couple of return line leaks and replaced the filter, I have also tighted hose clamps etc. The system seems to be tight, could the lift pump or the ftv be letting air in the system? or what does the small hose do that comes back to the filter outlet do? it seems that the air could only be getting into the system from the supply side not the return side??? I was going to bypass the ftv next with just the rear tank and see what happens. Both tanks are full I had only put about 50 miles on it, and yes the gauge is pegged to the right on both tanks ( work on that later...) Thanks for the help