What was found
(CAN) CAPTAIN REPORTS GEAR DISAGREE ON TAKE OFF, MAIN GEAR LIGHTS WENT GREEN MOMENTARILY, AND THEN STARTED FLICKERING BETWEEN RED AND AMBER INDICATIONS. NLG DIDN`T GO GREEN AT ALL AND FLUCTUATED BETWEEN RED AND AMBER INDICATIONS. RETURNED TO FIELD, DID NOT LAND OVERWEIGHT. CORRECTIVE ACTION: MX REPLACED BALANCE RELIEF VALVE AND PSEU. OPS CHECK GOOD. FUNCTIONAL FLIGHT SCHEDULED. SEE ALSO FAA SDR NR 2018080401569/SWIA201844279. SEE ALSO FAA SDR NR 2018080401572/SWIA2018002194280). (TC NR 20180222016).