TM 9-2320-209-10-1 f. Gravity Discharging the Tank Sections. TOOLS: 2-inch spanner wrench FRAME 1 1. 2. 3. 4. 5. 6. 7. Start engine. (Refer to para 4-6b.) Park truck near area where water is to be let out. Stop engine. (Refer to para 4-6e.) Open rear compartment doors. Turn left, and take dust cover (1) off gravity delivery line suction valve adapter (2). Put 1 1/2 x 2-inch reducer coupling (3) onto gravity delivery line suction valve adapter (2), turn right, and use 2-inch spanner wrench to tighten. Place one end of discharge hose (4) onto coupling (3), turn right, and use spanner wrench to tighten. Place discharge nozzle (5) onto other end of hose, and turn to right to tighten. GO TO FRAME 2 4-192