Where is the drain plug for the transmission fluid for a 1965 Ford Mustang?

No drain plug, you have to drop the pan, but you need to do that anyway to replace the filter. Nope, no drain plug. The vehicles that have ones with drain plug you still have to replace the filter anyway. :) You have to drop the tranny pan. Make sure you scrape the old gasket off well and torque the bolts to the right specs. Good luck. Hope I helped. As the other people have said, there is no drain plug, you have to drop the pan to drain the tranny. The very important part is when you scrape the old gasket off DO NOT use a metal scraper, use a plastic scraper so you do not put any gouges or striations on the two faces that will be accepting the gasket (the pan and the tranny) if you do damage these surfaces you will end up with leaks.