TM 10-3930-664-24 5. Measure distance between top of inner rail (26) and top of outer rail (31) on both sides.  Distance shall be 1.0   inch.      If   required,   adjust   mainlift   chains   as follows: NOTE Make  sure  that  both  mainlift  chains (22)   are   adjusted   evenly   to   ensure that inner rail raises level. a. If  distance    is    less    than    1.0    inch,  lengthen mainlift  chain  (22)  by  loosening  nuts  (14)  and turning nut (17) to the left until correct distance is achieved. c. If   distance      is   greater   that   1.0   inch,   shorten mainlift  chain  (22)  by  loosening  nuts  (14)  and turning nut (17) to the right until correct distance is achieved. d. Tighten nuts (14). FOLLOW-ON MAINTENANCE: Adjust   sideshift   chains   in   accordance with Operators Manual 2-417