What was found
AIRCRAFT WAS GROUNDED: UPON BEING NOTIFIED THE 4R DOOR ARMING LEVER WAS STIFF IN ITS MOVEMENT, THE FLIGHT ATTENDANTS ATTEMPTED TO CHECK THE FUNCTION OFTHE LEVER AND FOUND THAT NOT ONLY WAS IT VERY STIFF BUT WAS ALSO MAKING GRINDING NOISES FROM THE INSIDE OF THE DOOR. THEY MENTIONED IT WAS DIFFERENT THAN ANYTHING THEY'VE EXPERIENCED IN TRAINING OR PAST OPERATIONS. MAINTENANCE CHECKED THE LEVER AND FOUND THAT WAS HARD TO MOVE WITH LOUD GRINDING SOUNDS AS REPORTED BY THE FLIGHT ATTENDANTS. MAINTENANCE ACCOMPLISHED AN INSPECTION OF THE AFT RIGHT PASSENGER / CREW DOOR INTERNAL STRUCTURE WITH NO ISSUES REPORTED. MAINTENANCE LUBRICATED THE ARM / DISARM MECHANISM PER AMM 12-22-52.