TM 9-2320-303-10 Table 2-1.  Preventive Maintenance Checks and Services (PMCS) for M915A4 (Con't). Location Item To Check/ Not Fully Mission Item No. Interval Service Procedure Capable If: 23 (Con’t) After Overall View b.   Check  front  gladhands for   damage.      Ensure that gladhand vent holes  are  not  plugged. Ensure     that     dummy couplings are installed. c.  Check truck for obvious    damage    that would impair operation. c.  Damage that would impair operation is evident. d.   Check   for   damage   to front service and blackout lights and marker clearance lights. d.   Lights are damaged. 23 After Wheels WARNING and Tires Operating    truck    with    an    underinflated    or defective tire may lead to tire failure and loss of steering   control.      Damage   to   equipment   or injury to personnel may result. Visually check all left side tires for defects, underinflation,  or  loose  or missing   wheel   studs   or lug nuts. Tire     is     missing,     deflated, unserviceable, or two or more wheel studs or lug nuts are missing. 24 After Front Axle Wheel Bearings Check  that  lubricating  oil is   visible   in   sight   glass (25)  and  rubber  plug  (24) is  installed.    If  oil  is  not visible in sight glass, remove plug and add until level   is   even   with   plug opening (Appendix F). 2-37