TM  10-3930-643-34 HYDRAULIC  SYSTEM  TROUBLESHOOTING  AND  MAINTENANCE. 12-1. Hydraulic  System  Troubleshooting. MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION e. LOAD SLOWLY DROPS WITH LIFT CONTROL LEVER IN “HOLD”. Step 1. Check loader control valve spool to determine if hydraulic fluid is leaking past it, refer to paragraph 12-3. Repair or replace loader control valve, refer to paragraph 12-3. If hydraulic fluid is leaking by the valve spool in the fork valve assembly,  refer  to  paragraph  12-5. If hydraulic fluid is leaking by the valve spool in boom assembly valve,  refer  to  paragraph  12-7. Step 2. Check to determine if hydraulic fluid is passing from hold side to opposite side of hydraulic lift cylinder piston, refer to paragraph 12-12. Repair  hydraulic  lift  cylinder,  refer  to  paragraph  12-12. f. MOMENTARY DROP OF LOAD WHEN LIFT CONTROL LEVER IS MOVED FROM ‘HOLD” TO “RAISE” OR “RAISE” TO “HOLD”. Step 1. Check for scored or worn check valve poppet or seat in loader control valve, refer to paragraphs 12-3, 12-5 and 12-7. Replace  appropriate  valves. Step 2. Check for valve poppet held off its seat in loader control valve, refer to paragraphs 12-3, 12-4, 12-5 and 12-6. Clean system. Check for foreign matter after cleaning. Step 3. Inspect for broken check valve spring, refer to paragraphs 12-3, 12-4, 12-5 and 12-7. Replace  any  broken  or  defective  spring. 12-5