transmission filter help
 

I have a 1998 v6 mustang with a 4 speed automatic transmission. I was changing the filter today and found a round plastic ball (1/2 inch dia. or so) with a rod sticking out of one end. It looks like the ball has an o-ring recessed into it. Since it was lying in the oil pan when I pulled it I have no idea where it went. Can anyone help me? A picture or diagram would be really helpful.
Thanks, Frank

Re: transmission filter help
 

That is a plug the factory installs in the dip stick hole upon assembly of the transmission to keep dirt out. When the dipstick is installed, they just push the plug into the pan.

I serves no purpose after that.