What was found
GEAR DISAGREE IN FLIGHT DURING CRUISE WHILE LANDING LEVER WAS UP, PER QRH PULLED MANUAL LEVER AND MESSAGES DISAPPEARED. MESSAGE LASTED FOR ABOUT 15SEC, THE NOSE GEAR SHOWED A RED BOX, HYD PRESSURES AND QUANTITY WAS ALL IN GREEN, THERE WERE NO OTHER ASSOCIATED MESSAGES AT THE TIME. AIRCRAFT RETURNED TO THE AIRPORT KIAD ****AIRCRAFT REMOVED FROM SERVICE*** PERFORMED FUNCTIONAL TEST OF LANDING GEAR EXTENSTION AND RETRACTION SYSTEM IAW 32-30-00 OPS TEST GOOD AT THIS TIME.