What was found
GEAR WOULD NOT RETRACT AFTER TAKEOFF. DURING RETURN TO DEPARTURE, RECEIVED "TAKEOFF, FLAPS, GEAR, TRIM" AURAL WARNING. EXECUTED A NORMAL LANDING AND IMMEDIATELY AFTER TOUCHDOWN RECEIVED LG AIR/GROUND FAIL AND IC 1-2 WOW INOP EICAS MESSAGES. AFTER PARKING TRIED TO CONNECT GPU BUT PLANE WASN'T SEEING IT ON ELECTRIC PAGE - SHUTDOWN NR 1 ENGINE AND LOST CAPT PFD + FO MFD. ON SHUTTING DOWN NR 2 ENGINE THE F/O PFD. R & R LANDING GEAR ELECTRONIC UNIT IAW AMM 32-32-01. OPS CHECK GOOD. NO FURTHER DEFECTS NOTED.