TM 5-3895-383-24 Table 1-1.  Unit Preventive Maintenance Checks and Services – CONT. Location Item Man- Item to be Not Fully Mission No. hour Checked or Capable If: Interval Serviced Procedure WARNING ·  Fuel is very flammable and can explode easily.        To    avoid    serious    injury    or death: ·  Keep at   least  a  B-C  fire  extinguisher within  easy  reach  when  working  with fuel or fuel system. ·  When refueling, stop engine, and apply parking brake.  Ensure no open flame is near area.  Never smoke while working with fuel.  Never add fuel when engine is running.  Do not have a driver seated when adding fuel. ·  Ground   fuel   funnel   or   nozzle   against filler   neck   to   prevent   sparks   and   be sure to replace fuel tank cap.  After fuel is    added,    securely    close    fuel    cap assembly;  a  loose  cap  assembly  can cause a fuel leak or be a fire hazard. ·  Never  overfill  the  tank  or  spill  fuel.    If fuel is spilled, clean fuel up immediately.      Before   starting   vehicle, check   that   no   fuel   is   spilled   on   or around vehicle. 17 500 H 0.5 Fuel System Replace fuel system upper and lower secondary filters or S Secondary Filters (Page 1-102). 18 500 H 0.1 Fuel system Replace fuel system water separator or S Water Separator (Page 1-104). 19 500 H 0.1 Cooling System Check coolant concentration.  Add coolant if or S concentration ratio is incorrect (Page 1-74). 20 1,000 H 0.5 Drum Drive Change oil (Page 1-81). or A Gearbox Oil 20.1 1,000 H 0.5 Wheel Drive Change oil (Page 1-127). or A Gearbox Oil 1-14