98 S10 leaking ATF when hot
 

https://cimg6.ibsrv.net/gimg/chevrol...e02554adae.png

The transmission functions properly, no slipping or anything. When it gets to a normal operating temperature, it starts spewing fluid out of this little vent type cover on the bottom side of the transmission. Like I said, when it's cold and hasn't warmed up yet it won't leak. The transmission was rebuilt 2 years ago. Any ideas?

Is the fluid level normal?