What was found
AFTER TAKEOFF SELECTED GEAR UP EICAS INSTANTLY WENT FROM DOWN TO UP WITH NO TRANSITION INDICATION. CHECKED RMU, RMU INDICATED DOWN & LOCKED, EICAS INDICATED UP. GEAR POSITION IN QUESTION RAN ABNORMAL LG EXTENSION CHECKLIST, GEAR CAME DOWN WITH GEAR ELEC OVERRIDE SWITCH IN GEARS & DOORS POSITION. DECLARED EMERGENCY, LANDED SAFELY MIA. R & R LGEU IAW AMM 32-32-01 & PERFORMED OPERATIONS CHECK IAW AMM 32-30-00.