TM 9-2320-361-20 14-31. PRIMARY HEATER AIR INLET DUCT REPLACEMENT This task covers: a. Removal b. Installation INITIAL SETUP: APPLICABLE MODELS M109A3 and M185A3 REFERENCES (TM) TM 9-2320-361-10 TM 9-2320-361-20P EQUIPMENT CONDITION Parking brake set (TM 9-2320-361-10). Remove four screws (1) and duct (2) from van body (3). b. Installation Install duct (2) on van body (3) with four screws (1). 14-47