The Stovebolt Site Forums The Shop Area Driveline M21 Muncie 4-Speed Broken Reverse Shift Stud

Agreed. It's been cracked for a long time, it has heavy rust in the cracked area.

This trans was made in 1965. They changed the design in '69 from a 5/16" UNC thread to a 3/8" tapped hole... doesn't sound like much, but it increases the strength by 44%.