What was found
HYDRAULIC RESERVOIR: DURING FLIGHT AT FLIGHT LEVEL 400 WE RECEIVED A HYD LOW LVL ANNUCIATOR. WE RAN THE QRH AND ANNUCIATOR REMAINED ON. REMOVED UH EDP PN 9912062-4 SN 6008 DUE TO AIRCRAFT LOSS OF HYDRAULIC FLUID AND INSTALLED THE NEW UNIT LISTED ABOVE IAW AMM AMM 29-11-03, OPS AND LEAK CHECK GOOD. 2 REMOVED R/H EDP PN 9912062-4 SN 6048 DUE TO AIRCRAFT LOSS OF HYDRAULIC FLUID AND INSTALLED THE OVERHAULED UNIT LISTED ABOVE IAW AMM 29-11-03, OPS AND LEAK CHECK GOOD.