This might help though it's a 722.3, not a 722.4 like you have - http://www.peachparts.com/shopforum/diesel-discussion/345809-help-broken-shift-lever.html

I doubt that's what's broken if it happened while rolling. Even slamming the tranny into P at speed will damage other parts of the transmission but unlikely that rod. It's tight quarters in a 124 but maybe the bushingless shift rod fell out of the bell crank or the bell crank came off the transmission.

Sixto
87 300D