Hey guys, this may sound stupid but I'm new to this whole dual tank business... Right now it's switched to "Main", and I need to put some gas in it. The problem is, I don't know if the front or rear tank is the main. The rear tank looks bigger, so I'm guessing that's the main tank, but I just want to double check with someone. Thanks

Edit: Maybe the front is the main tank? That actually makes sense if that is true.

 

I have a 77 f250 and my rear tank is the main.

 

51fordf5 what year is teh truck, if both tanks r under teh truck,teh rear is the main

 

D'oh! I guess I'm gonna find out if the aux tank is working properly lol. To be safe I did put a little bit in the rear tank. Should've waited for someone to respond but stupid me got impatient haha.

Edit: Oh yeah, and it's a 78 F250 SuperCab. It's got stock dual tanks with the switch by the A/C and heat controls.

 

Yeah, the rear (aft axle as Ford calls it) is the main tank. The "AUX" is the front tank (Ford calls these "mid-ship" tanks)

 

Alright, thanks. Once I flip the switch to change tanks, is there any way to tell if it actually switched to the Aux tank? I mean is there like any type of motor I should listen for (not that I'd be able to hear it over the exhaust)?

 

It's a simple solenoid activated valve, no motor. The most you would hear is a "click" or maybe "thump" not much more. I never heard mine cycle.

 

if your fuel gauge is working, it will move when you switch over.

 

The switch will always swap the gauge reading but I've had a couple of instances where the valve was bad and the tank didn't switch, so you were still on the empty tank.