Gas vs Diesel Gas Tank Sending Unit

[andyh1956]

All my 18 wheelers & diesel eqpt return fuel to the top of the tank.
Here's how to plumb this up with two tanks & not worry with the switching valve apparatus & you will only need one fuel level sender:
All new trucks are plumbed thusly-
One hose from the engine to a tee. From the tee equal length hose to each tank, this is for suction.
For the return from the engine to the return tee. This tee has two little "Flappers" in it that act as check valves & the return fuel has to reach a min "Cracking" pressure to open the flappers & continue on to the fuel tank. The hoses from the return tee to tank should be equal length also.
This way you will draw from both tanks & return to both tanks equally.
You are gonna have to fill both tanks independently anyway so why not design the system as simple as possible!
Any Navistar / Freightliner / Peterbuilt place or better yet LKQ yard will have these valves.