That's a simple pipe thread. Use an NPT tap (I think it's 1/2" NPT) to clean up the threads and put a 1/2" to 3/8" brass reducer bushing into the case with red LocTite if necessary to get a new thread for a plug to fit. The transmission doesn't know or care what size drain hole it has. Make sure someone hasn't overtightened the plug and cracked the case. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!