OPERATION OF MEDIUM WRECKER (Contd)
For lift-tow operations (M936A2):
Remove two retainer and adjustment pins (18) and (19) from shipper brace adjustment holes (17).
Elevate boom until third hole from bottom of two shipper braces (1) are aligned with pin holes (17). Replace shipper brace
adjustment and retainer pins (18) and (19).
Attach whiffletree (3) to reversed lift shackles (4) of disabled vehicle.
Remove line, assembly, and sling from crane hook before lifting boom.
Remove two retaining pins (11) and adjustment pins (10). Slide out leg extensions (9) to third hole
(seventh hole on vehicles with winch) from clevis (13) end. Replace adjustment and retaining pins (10) and (11). Attach
clevis (13) to each clevis (13) end and secure in place with clevis end retainer pin (14).
Loosen two tension adjusting nuts (7) on clamps (8). Position one clamp (8) against front axle of
disabled vehicle and wrap clamp chain (6) around axle (16) and back up through clamp (8). Fasten chain (6) to clamp (8).
Lock in place by turning tension adjusting nut (7) until secure. Repeat step with second clamp (8) on opposite side.
Secure clevis (13) and clevis end retainer pin (14) with clamp (15).
Install other end of towbar (12) to wrecker pintle hook (20), and secure with retaining pin (21). Lower
crane block (2), and insert hook (5) facing away from wrecker through center hole of whiffletree (3).
Install safety chain on towed vehicle, wrap chain three times around towbar, and attach chain to right
rear lift-shackle (4) of wrecker. Connect emergency and service air connectors (23) to half connectors (22) on each
vehicle. Disengage brakes and place transmission, transfer case, and PTO of disabled M939A1/A2 series vehicle in
neutral. Fully retract boom, and hoist crane block (2) up until front wheels of disabled vehicle are off ground and towbar is
level (parallel to ground).