Here we go again...Trans fluid dumping.

[eightbanger]

I have th400 and had a leak a while back where the fluid would dump after a drive which I tracked down to a small hole on top of my trans, but it did not happen all the time...so not knowing what I was doing I filled the small hole with bondo then posted on the board about it,(pics here)
http://67-72chevytrucks.com/vboard/s...d.php?t=296816 and found out that I should not have filled that hole as preasure would build up in the tranny. Also that there should be a small metal breather tube comming from the tranny where the hole is but it has been removed or broken off over time, anyway after unpicking the bondo no further probs until now. It has dumped big time through the dipstick sprayed the dizzy, fire wall and poured all over the exhaust...scared it was gona catch fire on the way home, smoke everywhere......so is it preasure related? and why would preasure build up? is it overheating? the fluid was vey hot when it was coming out, why would it overheat? have not been able to use my truck all week as soon as I drive a few hundred yards I can see the smoke trail behind me and the gears are not shifting smoothly now, there is little or no fluid left in there now.
I guess my main question is....can I find and fix the prob myself? (with the help of you guys) or is this a job for the pro's??