What was found
FLT 9804, CREW REPORTED, CLIMBING THRU 31,600 FT, RECEIVED A LT BLEED DUCT WARNING MESSAGE. BOTH PACKS SHUTOFF. PERFORMED AN EMERGENCY DESCENT TO 10,000 FT. LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED FWD CLAMP IAW MM 21-53-14. OPERATED BOTH PACKS FOR 90 MINUTES AND COULD NOT DUPLICATE BLEED LEAK. REMOVED AND REPLACED THE VENTILATED TEMPERATURE SENSOR (FWD) IAW AMM 21-61-06. OPERATED PACK ON AUTO IAW AMM 21-51-00. OPS CHECKED GOOD. REMOVED AND REPLACED NR 2 PACK DISCHARGE PRESSURE SENSOR IAW AMM 21-51-24. OPS CHECKED GOOD.