As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT INITITATED DUTCH ROLL DURING CLIMBOUT AND PROGRESSIVELY GOT WORSE WITH THE HIGHER CLIMB. ROLL TOOK PLACE WITH OR WITHOUT AUTO PILOT ON AND OFF, WITH YAW DAMPER SWITCH ON OR OFF. ACCOMPLISHED RUDDER CONTROL TAB INSP/TEST IAW DC9 MM 27-20-02-04. NO DEFECTS NOTED. LUBRICATED RUDDER PACKAGE.