12-86. TM 9-2320-361-20 This task covers: a. Removal b. Installation INITIAL SETUP: APPLICABLE MODELS EQUIPMENT CONDITION M764 •Parking brake set (TM 9-2320-361-10). REFERENCES (TM) •Vertical drivechain cover removed (para. 12-87). TM 9-2320-361-10 TM 9-2320-361-20P • NOTE The replacement procedure for first and second reduction leveling worm drivechains are the same. This procedure covers second reduction drivechain. Vertical leveling worm drivechain may have cotter pins or a spring clip fastener for a retainer. This procedure covers a spring clip fastener. • 1. Loosen nut (5) and screw (8). 2. Hold shaft (7) and turn eccentric bushing (6) until first and second reduction drivechains (1) and (4) are loose. 3. Remove spring clip (11) and link plate (10) from connecting link (9). 4. Remove connecting link (9) from second reduction drivechain (4) and remove second reduction drivechain (4) from sprockets (2) and (3). 1. Install second reduction drivechain (4) on sprockets (2) and (3) and install connecting link (9) on second reduction drivechain (4). 2. Install link plate (10) and spring clip (11) on connecting link (9). 3. Hold shaft (7) and turn eccentric bushing (6) until first and second reduction drivechains (4) and (1) are tight. 4. Tighten nut (5) and screw (8). 12-138