so I've filled my dual tanks twice now, and each time I get to the bottom of the first tank (Right hand side), I switch to the left and it only shows half full I've replaced both gas caps so I know they're not leaking, and they're locked. I know that the guage isn't just wacky since both times I've had to add another 12 gallons to the left tank to bring it full- so now I've lost close to $60 in gas somehow!!!!! I know it's not leaking cause there's no drips or gas smell, or wet areas anywhere in the area. My question is, if I have the tank selector on the right side, what is stopping the gas from being drawn from the left side? If I'm severely off camber off road, will gas from the left tank flow to the right and vice versa? Will there be some sort of vacuum trhough the right tank that draws a bit from the left as I'm driving? In tank pump? How does it work on a '78 K20 with dual tanks? I'm just trying to figure out where 25 gallons of gas went!!!!