TM10-3930-660-20 18-4.    TANDEM GEAR PUMP ^- TEST/REPLACE (Cont’d) CAUTION Tandem gear pump must be purged of air before engine is started. Refer to para. 18-3 for purging instructions. Failure to purge air as directed may result in severe damage to tandem gear pump. 3. PURGE AIR FROM THE TANDEM GEAR PUMP, PARA. 18-3. 4. INSTALL TRANSMISSION ACCESS COVER, PARA. 16-6. TESTING NOTE Both the large pump section and the small pump section of the tandem gear pump are tested in the same manner. 1. 2. 3. 4. 5. REMOVE TRANSMISSION COVER, PARA.  16-6. PREPARE AND SET UP THE IN-LINE FLOWMETER FOR TESTING. DISCONNECT PUMP OUTLET HOSE (1) FROM THE PUMP SECTION BEING TESTED. CONNECT A TEST HOSE FROM THE OUTLET SIDE OF THE SECTION BEING TESTED TO THE INLET PORT OF THE FLOWMETER. CONNECT THE HYDRAULIC HOSE (1) REMOVED IN STEP 3. TO THE OUTLET PORT OF THE FLOWMETER. Use the STE/ICE kit to monitor engine speed. The hydraulic pumps are tested at 6. 7. specific engine rpms. START THE ENGINE, TM10-3930-660-10. IF THE LARGE PUMP SECTION (2) IS BEING TESTED, ADJUST THE ENGINE SPEED TO 2400 RPM, ADJUST PRESSURE TO 2500 PSI, AND READ THE FLOW IN GPM . 18-9