My Rear end is smokin hot!

[shmoov69]

Ok, it's in my car because I ain't got a rearend! Lol
first off, 9" rear with 3.00 gear and a Locker.
last weekend at the MMCC event my car puked out rear end fluid/grease out of the vent tube after around 9 laps or so around the road course. It dis it twice after about the same amount of laps, so I think it is legit. I jacked it up answer it on stands for about 15 minutes. Then I got under it to spray it off with brake cleaner. The tubes were fine, the mufer was even fine. But I sprayed the pumpkin and it sizzled it was STILL so hot! After a minimum of 15 minutes!!
Now my questions, is the fluid junk now? It had Castrol Syntec fluid in it.
What should I be running? And does anyone have a good idea for an overflow tank that will fit? Or ideas on anything else?

Thanks!