What was found
DURING CLIMB, EXPERIENCED SEVERE VIBRATION IN NOSE GEAR AREA AFTER GEAR RETRACTION. RECYCLED GEAR BUT DID NOT HELP. AIR TURN-BACK TO DFW. VIBRATION STOPPED ON APPROACH. OPERATED DOORS, INSPECTED FOR DAMAGE, FOUND NONE. LUBRICATED DOOR ACTUATORS, OPS CHECKED GOOD IAW DC8 MM 32-22-1.