You don't want it spilling out of the fill hole, if it is, you overfilled.
Also, don't fill using a pump, pull the shifter and just pour it in through there. Much more accurate and easy to do it. You want 3 quarts and then literally be anal retentive about ONLY doing .2 more because if you overfill you can have issues as Ford found out. Which is why it is 3.2 quarts now.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.