STROKEXD : Thats exactly what my old auto did before it was completely toast in Feb 2003. Part the issue was the auto was getting to warm under race conditions and long drives. It used to vent oil all the time.
The issue is keeping the oil cool enough. When it gets warm/cooks it vents. Then having minimal fluid in the box destroys the clutches.
Whats your box have in it? As mine was supposed to be a top notch box and it was found to be a stocker with a shift kit. Nothing more. If it's only got 4 clutches it's a stocker build.
I've since had it redone as you know and I blew it even quicker.
Due to the build being better supposedly
It no longer vents.
Problem is now your trans is probably already toast. Try running two trans coolers. I ran two 12,000lb B&M coolers and no longer have any heat issues. Slipping clutches will also cause heat, which will cause the oil to boil and vent.