(3) Remove  air  hoses  and  fittings  from  feed motor (4) (see paragraph 5-3). WARNING Feed   motor   and   gearbox   assembly   is heavy. Use     an     overhead     hoist     to     remove assembly. Secure assembly to overhead hoist before removing mounting   hardware.      Failure   to   follow this   warning   could   result   in   personnel injury and equipment damage. (4) Remove   four   bolts(5),   lockwashers   (6), and   two   square   washers   (7)   securing   gearbox   (8)   to mount    (9).        Remove    feed    motor    (4)    and    gearbox. Discard lockwashers. (5) Loosen setscrew (10) and remove sprocket (11) and key (12) from gearbox shaft (13). b. Installation. (1) Install    key    (12)    and    sprocket    (11)    on gearbox shaft (13).  Tighten setscrew (10). NOTE Square    washers    are    used    on    Inner mounting bolts only. (2) Install  feed  motor  (4)  and  gearbox  (8)  on mount (9) using four bolts (5), new lockwashers (6), and two square washers (7). (3) Ensure  that  sprocket  (11)  is  aligned  with other sprockets.  Adjust position if necessary. (4) Install air hoses and fittings on feed motor (4) (see paragraph 5-3). (5) Ensure     that     drive     chain     (3)     properly engages all sprockets.  Install master link (2) and secure with four new cotter pins (1). (6) Service gearbox (LO 5-3820-241-12). (7) Adjust  chain  (see  paragraph  5-13).    Page B-1.  Appendix B is superseded as follows: APPENDIX B MAINTENANCE ALLOCATION CHART (MAC) Section I.  INTRODUCTION B-1. The Army Maintenance System MAC a. This  introduction  (Section  I)  provides  a  general explanation    of    all    maintenance    and    repair    functions authorized    at    various    maintenance    levels    under    the standard Army Maintenance System concept. b. The    Maintenance    Allocation    Chart    (MAC)    in Section  II  designates  overall  authority  and  responsibility for   the   performance   of   maintenance   functions   on   the identified end item or component.  The application of the maintenance functions to the end item or component will be  consistent  with  the  capacities  and  capabilities  of  the designated maintenance levels, which are shown on the MAC in Column (4) as: Unit-includes two subcolumns, C (operator/crew) and O (unit) maintenance. Direct Support-includes an F subcolumn. General Support-includes an H subcolumn. Depot-includes a D subcolumn. c. Section   III   lists   the   tools   and   test   equipment (both  special  tools  and  common  tool  sets)  required  for each  maintenance  function  as  referenced  from  Section II. d. Section   IV   contains   supplemental   instructions and    explanatory    notes    for    a    particular    maintenance function. B-2. Maintenance Functions. Maintenance functions    are    limited    to    and    defined    as follows: a. Inspect.    To  determine  the  serviceability  of  an item    by    comparing    its    physical,    mechanical,    and/or electrical     characteristics     with     established     standards through examination (e.g., by sight, sound, or feel). 21