What was found
EWR---CO3541, AIRCRAFT AIR RETURN TO EWR. CREW REPORTED, WHEN LANDING GEAR BROUGHT TO RETRACT, RECEIVED ON EICAS LG/LEVER DISAGREE MESSAGE, ALSO LEFT MAIN ON EICAS WAS RED CROSS HATCHED(INDICATION), NOSE AND RIGHT MAIN RED DOWN INDICATION. MAINTENANCE TROUBLESHOT PROBLEM AND REMOVED AND REPLACED LGEU IAW REFERENCE EMB 145 MM 32-32-01. AIRCRAFT RETURNED TO SERVICE.