Just thought i'd share something I did.
Found a 50 gallon Transfer Flow fuel tank on CL.
Stripped out the wire harness parts I needed and
wired into AUX 5 on upfitter panel as the TRAX2
wouldn't work. I used a RDS fuel neck kit from Northern Tool.
Fit was close..7/8 of a inch to spare in front of picture frame adapter. Total cost,about $400.00
Hardest part is the fuel neck mod. Remove it from the truck.
On a SWB truck it is tight. Now I have 81 Gallons total.The
pump on the tank transfers @ 20 GPH.

 

Nice.

I'd like an aux tank but I cant afford the additional bed weight give how big my 5th wheel already is.

 

I built a frame to attach to a Pullrite 4439 picture frame to mount my aux 100 gal tank for fuel oil.

 

Great idea.The frame could be adapted to fit so many different things.