92 4.9L AUTO. WHILE SITTING IN THE TRUCK TALKING TO FRIEND WITH IT RUNNING IN REVERSE SITTING STILL TRANSMISSION FLUID STARTING SPUING OUT OVER FLOW TUBE AND BURNING ON THE EXHAUST. I PULLED AWAY AND IT SMOKED A LOT SO I PULLED OVER AND SHUT IT OFF TO COOL DOWN. WHEN I RESTARTED IT AND DROVE HOME IT SEEMED OK. BUT WHY DID IT DO IT??