Adding a drain plug 727
I typically weld a steel pipe coupler 1/8” or 1/4” to side of pan near the bottom edge and use a pipe plug - it also gives option down the road to add sending unit to pan if you want trans temp gauge. Make sure it is steel and not cast steel. Cast steel looks like it has formed bars (like Home Depot cheap) and get an electrical conduit style- real steel and smooth outer housing. Sometimes on the plumbing or electrical section of most hardware stores. Or oven better a hydraulic 1/8” or 1/4” coupler. Dependent on your taste for size. Typically galvanized so you need to grind off coating to bare metal. I like to drill hole in pan and slide the fitting inside 1/2 way- looks cleaner.
SN- draining down pan is way easier with plug vs. dumping oil all over the place when changing the filter.