TM9-2320-361-10 2-31. OPERATION OF PIPELINE CONSTRUCTION MAINTENANCE TRUCKS (Contd) (4) Insert gin pole links (1) into adapters (3) and secure with holding pins (5), lockwashers (2), and screws (4). (5) Insert trunnion (10) through ring ends (9) of boom chains (15) and yoke ends (8) of gin poles. (6) Turn trunnion (10) until it locks into place. (7) Install A-frame sheave assembly (13) in trunnion (10), and secure with retaining pin (11) and two cotter pins (12). (8) Insert boom chains (15) through lashing rings (14) on ends of truck bed, double chains (15) back and lock hooks into chains (15) about 15 links from lashing rings (14). (9) Install tailboard sheave assembly (6) in center sheave mount well with retaining pin (7) and two cotter pins (16). (10) Loosen nuts (17) and (23), unscrew retaining pins (18) and (24), and turn side plates (19) and (22) 90°. 2-156