TM10-3930-660-20 18-4.    TANDEM GEAR PUMP - TEST/REPLACE (Cont‘d) 8. IF THE SMALL PUMP SECTION (3) IS BEING TESTED , ADJUST ENGINE SPEED TO 1800 RPM, ADJUST PRESSURE TO 2500 PSI , AND READ THE FLOW IN GPM. 9. THE HYDRAULIC PUMP SECTIONS MUST MEET THE FOLLOWING SPECIFICATIONS : LARGE PUMP SECTION - 36.3 GPM AT 2400 RPM SMALL PUMP SECTION - 13.5 GPM AT 1800 RPM 10. REPLACE PUMP IF EITHER SECTION FAILS TO MEET OR EXCEED THE SPECIFICATIONS GIVEN IN STEP 9. REFER TO THE REMOVAL AND INSTALLATION SECTIONS OF THIS PARAGRAPH FOR REPLACEMENT INSTRUCTIONS. 11. TURN ENGINE OFF, TM1O-393O-66O-1O. ALLOW HYDRAULIC SYSTEM TO COOL DOWN BEFORE PROCEEDING. 12. DISCONNECT TEST HOSE FROM OUTLET SIDE OF SECTION TESTED AND FROM INLET PORT OF FLOWMETER. 13. DISCONNECT HYDRAULIC HOSE (1) FROM OUTLET PORT OF FLOWMETER AND CONNECT HOSE (1) TO OUTLET SIDE OF SECTION TESTED  . 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. 14. PURGE AIR FROM THE TANDEM GEAR PUMP,  PARA  18-3. 15. INSTALL TRANSMISSION ACCESS COVER, PARA. 16-6. 18-10