What was found
HYD Y RSRV OVERHEAT MESSAGE ON CLIMB OUT. T/S PER A320 TSM 29-3-00-810-802-A. LT Y SYS E PUMP RUNNING FOR 20 MINS. RCVD Y SYS OVHT FAULT. FOUND Y SYS OVERSERVICED BY 1 GALLON. DRAINED ALL FLUID AND R/R TEMP TRANSM SWITCH 3381GR. OPS TEST FAILED. INSTALLED IS BORROWED UNIT. CONT T/S PER TSM 29-13-00-810-802-A. REMOVED CHECK VALVE AND INSPECTED W/ NTF REINSTALLED SAME. REMOVED LP FILTER. INSPECCTED. W/ NTF REPLACED SAME AS PERCAUTION. REMOVED HP FILTER. FOUND FILTER W/ HEAVY DEBRIS. IAW AMM 29-13 L FILTER WILL REQ LEAK CHK. REMOVED AND REPLACED YELLOW HYD SYS HP MANIFOLD IAW AMM 29-13. WILL REQ LEAK CHK. C/W LEAK CHK OF HP MANIFOLD YELLOW SYS. NO LEAKS NOTED PER A320 AMM 29-13.