TM 10-3930-669-10 3-13.  FORK REPLACEMENT/ADJUSTMENT. a. Removal. (1) Unlock latch (1) on fork (2). WARNING Fork weighs 86 lbs (39 kg).  Do not remove without aid from an assistant or personnel injury may result. NOTE Forks  must  be  removed  from  the  center  of  the  carriage.    Bottom  rung  on  carriage  is  slotted  for removal and installation. (2) With the aid of an assistant, remove fork (2) from carriage (3). b. Installation. CAUTION Do not drop forks against carriage.  Install forks on carriage easily.  Failure to do so will result in mast chain slack, which can cause the chain(s) to fall out of the sheave(s). (1) With the aid of an assistant, install fork (2) on carriage (3). (2) Lock latch (1) on forks (2). c. Adjustment. (1) Unlock latch (1) on fork (2). (2) Position fork (2) on carriage (3) to required position. (3) Lock latch (1) on forks (2). 3-20