Table 2-1.  Unit Level Preventive Maintenance Checks and Services HMMWV (Cont'd) ITEM NO. INTERVAL ITEM TO BE INSPECTED PROCEDURES 21 Semi- Batteries Annual a.  Inspect battery box and battery tray a.  Corrosion has bolts for corrosion and debris. If any made holes in metal corrosion is evident, wipe bolts battery box. and/or washers clean. If corrosion cannot be removed or the surface of bolts are pitted, replace bolts and/or washers (para. 4-80). b.  Clean slave receptacle and coat b.  Terminals corroded. with corrosion preventive compound (Appendix C, Item 24). c.  Check and record specific gravity c.  If cell is below of each cell. 1.225 specific gravity. d.  Inspect battery cables for frays, d.  Cables frayed, split, splits, or looseness. or loose. SPECIAL PURPOSE KITS 22 Semi- Cargo Shell Check adjustment of cargo shell door Annual Door (paragraph 11-13). 23 Semi- Rear Cargo Check rear cargo door for proper Annual Door operation. Rotate gas springs (para. 11-21) 180 degrees every six months and move left spring to right side and right spring to left side. TM 9-2320-280-20-1 Change 1 2-23 NOT FULLY MISSION CAPABLE IF: NOTE Add 4 points (.004) to specific gravity reading for every 10° above 80°F. .WARNING. •  Do not perform battery system checks or inspections while smoking or near fire, flames, or sparks. Batteries may explode causing damage to vehicle, injury, or death to personnel. •  Remove all jewelry such as rings, dog tags, bracelets, etc. If jewelry or disconnected battery ground cable contacts battery terminal, a direct short will result, causing injury to personnel, or damage to equipment. NOTE Reefer to TM 9-6140-200-14 for more specific details on battery maintenance.