Originally Posted by custom240sx

19mm...or 3/4" but the 3/4" is somewhat loose which isn't good. Take off the flywheel inspection plate from bottom of tranny, have someone hold a flathead screwdriver in there to jam it and then with a 3 foot breaker bar...break it loose. It WILL take effort to get off even with the 3 foot breaker bar. Threads on it are the same as a normal bolt NOT reverse.