TM 9-2320-363-20-1 Table 2-2.  Unit Preventive Maintenance Checks and Services (PMCS) for the M915 Family of Vehicles (Cont). Location Item Item to Check/ Not Fully Mission No. Interval Service Procedure Capable if: 19 Semi- Air System, e. Ensure that all air lines are not kinked (Cont) annual Brakes (All and that they are properly supported. Models) and Central Tire Inflation System (CTIS) (M917A1/ M917A1 w/MCS) 20 Semi- Air Leak test air conditioning system (page annual Conditioning 4-878). System, (All Except M915A2 and M916A1) 21 Semi- Under Vehicle, a. Inspect frame and side rails for annual Frame and cracks, breaks, bends, wear, Crossmembers deterioration, and loose bolts. b. Inspect crossmembers for weld breaks, wear, and missing capscrews and rivets. 22 Semi- Vehicle a. Inspect for corrosion in accordance annual Exterior with TB 43-0213. b. Inspect cab glass and doors, fenders, stowage boxes, and brackets for damage. WARNING Use   caution   when   taking   AOAP transmission oil sample. Transmission oil sampling valve is located   close   to   engine   exhaust pipe.          Failure     to     follow     this warning    may    result    in    serious burns. NOTE Transmission fluid must be sampled    initially    at    90    days    of operation,    as    prescribed    by    DA Pam    738-750.        Thereafter,    it    is sampled semiannually unless AOAP results indicate otherwise. 2-18.6  Change 3