Heed

My 85 4000q has developed a problem. The gas tank spills out the filler through the entire top half of the tank and runs down the side of my car. Needless to say i've only been putting $10 bucks in it at a time. No excessive 4 wheel slides, just daily driving. Gasket, gas cap, crack somewhere? Anyone else had this problem or know what is causing it?
Thanks ahead of time
Dan - Seattle