Fuel tank leak.

[Heo]

The fuel tank on my 92 leaks when it try to fill it to the brim. Once a few gallons have been used the leak goes away ( duh , but Im just trying to give all the details). The previous owner installed an auxillary tank in the bed and I assume that it ties into the stock tank around the filler neck..

So is there a connector for the filler neck to the tank that could be old and cracked.. Its been a little cold to go poke around under the truck..
Thanks!

[Ace]

Tighten up the pickup/sending unit. Rightey-tighty, lefty-loosy.

[mprmn08]

stick your lighter under there and see if you can see anything. just make sure someone video tapes it

[PToombs]

stick your lighter under there and see if you can see anything. just make sure someone video tapes it

OH, that's just not right! Good thing it's not a gasser!

I'd bet on the sender too. If it was the neck, it would leak outside the frame where it's easy to see. You may have a cracked fitting under there.

[GO OVRIT]

Most likely its what Ace and Pete said, but it could also be the big grommet around the filler pipe. Another not-likely possibility would be a broken vent.