As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF WITH A POSITIVE RATE OF CLIMB ESTABLISHED, WE ATTEMPTED TO RETRACT THE LANDING GEAR. THE LANDING GEAR HANDLE COULD NOT BE MOVED FROM THE DOWN POSITION. WE ATTEMPTED THIS SEVERAL TIMES WITH NO SUCCESS. WE DETERMINED THE BEST COURSE OF ACTION WAS TO RUN THE QRH ITEMS FOR BEING UNABLE TO RETRACT THE LANDING GEAR. AFTER RUNNING THE QRH ITEMS WE DECIDED TO RETURN TO ORD WHERE A NORMAL LANDING WAS MADE. NO EICAS MSG WERE PRESENT DURING THE ENTIRE EVENT.