What was found
2:00 INTO FLT, FLT 370 HYD 3 ELEV OFF ALER. HYD SYS 3 WAS AT 3.9 OVER NEXT FIVE MINUTES DROPPED TO 3.6. DEPRESSURIZED SYS UNTIL LANDING. AFTER LANDING QTY WAS DOWN TO 1.0 FOUND HYDRAULIC FLUID MISTING IN TAIL AREA AROUND HORIZONTAL STABILIZER TRIM MOTORS. FOUND HORIZONTAL STABILIZER TRIM MOTOR 1 BODY CRACKED AT MATING FLANGE ATTACH POINTS. REMOVED HS TRIM MOTOR SN MX-328050C. REF MD11 AMM 27-43-30-4 COMPLETE UP TO STEP 3, READY FOR TRIM MOTOR INSTALLATION. INSTALLED TRIM MOTOR. PERFORMED OPS CHECK. CHECKS NORMAL NO LEAKS NOTED. REF AMM 27-43-30-4.