TM 9-2320-361-34 15-36. INTEGRAL DERRICK MAINTENANCE THIS TASK COVERS: a. Removal c. Installation b. Inspection INITIAL SETUP APPLICABLE MODELS REFERENCES (TM) M764 TM 9-2320-361-10 TOOLS TM 9-2320-361-34P General mechanic’s tool kit EQUIPMENT CONDITION (Appendix B, Item 1) ● Parking brake set (TM 9-2320-361-10). MATERIALS/PARTS ● Outrigger arms lowered (TM 9-2320-361-10). . Derrick sheave removed (para. 15-37). GAA grease (Appendix C, Item 8) Three locknuts (Appendix F, Item 105) GENERAL SAFETY INSTRUCTIONS PERSONNEL REQUIRED ● Do not lower derrick below horizontal position. . Derrick tube is heavy. Provide adequate support Two when removing or installing derrick tube. WARNING . During removal and installation, only two teeth of worm leveling gear support derrick in horizontal position. Do not lower derrick below horizontal or derrick may fall and cause injury or death to personnel. ● Derrick tube is heavy. Provide adequate support for derrick tube during removal and installation over rack bar. Failure to do so may result in injury or death to personnel. NOTE Before removal of derrick, ensure there is 20 ft (6 m) clearance to the right of vehicle and 6 ft (2 m) clearance to the left of the vehicle. a. Removal 1. Lower derrick (7) to near horizontal and manually turn horizontal leveling worm gearshift (1) until derrick (7) is horizontal (TM 9-2320-361-10). Worm gear (10) will hold two teeth of worm wheel (9). CAUTION Do not feed rack bar more than 6 ft (2 m) from bottom of boring case while in horizontal position. Weight of rack bar may cause damage to pinions in boring gearcase. 2. Feed auger rack bar (8) 5 ft (1.5 m) out of derrick (7) (TM 9-2320-361-10). NOTE Assistant will help with step 3. 3. Loosen three locknuts (4) and screws (3) and remove derrick tube bar (5) from base (2) and auger rack bar (8). Discard locknuts (4). 15-126