Leaking Tranny Fluid

I just put a 4 barrel intake and carb on my 72 Dodge D100 318. I fired it up to check the timing and to adjust the edelbrock carb. It's an automatic 727. I put in N and pushed it out of the garage and fired it up. It is running in neutral while adjusting the carb. I look down and see a puddle of tranny fluid in the driveway. Its dripping between the oil pan and the tranny at the inspection cover. I clean the mess up, put the car in park and fired it up again, no leak. What do you guys think? I'll get back at this weekend. I have to get cleaned up for dinner out with the wife. Any advice will be appreciated. Thanks FABO.