Classic/Antique Car Repair: 1957 bel air powerglide transmission, drain bolt, auto tranny

Question
I have a huge transmission oil leak and I am trying to figure out where it is coming from...first there is no bolt or plug over the inspection window for the transmission. The drain bolt seems to be in place.  I bought the car recently with 5 miles on the odometer, I assume since the complete restoration about 7 years ago.  I assume the car sat for many years in storage..Car runs great...Have now about 3oo plus miles and one day in the garage it has a huge leak...Does it inspection hole need to be covered...what else might be the problem?

Answer
Eric ;
Hi - it might be leaking from the seals , can you tighten up any bolts on the tranny. They do sell a addative for auto. tranny leaks , it  might help  in your case. it is a tranny stop leak. as far as the insp. cover , I would not worry about it.