TM  1-1520-240-10            2-7-3 ture among all transmissions is indicated. The remaining positions are used for selecting a particular transmission fied by the oil temperature selector switch oil temperature indication. When selecting a particular switch position, be sure the switch is in detent. If the switch is not detent, the oil temperature indicator will indicate –70_C. Figure  2-7-2.  Transmission Main Oil Temperature Switch and Indicator 2-7-10.  Transmission Oil Cautions. Five transmission oil caution capsules are on the master caution panel. The capsules are labeled XMSN OIL HOT, XMSN   OIL   PRESS,   XMSN   AUX   OIL   PRESS,   and 712  NO. 1 AND NO. 2 ENG XMSN HOT,  714A   ENG 1 or ENG 2 XMSN HOT. These cautions, in conjunction with the transmission oil pressure and temperature indi- cators on the center instrument panel and the TRANS- MISSION OVERTEMP magnetic indicators, MAIN OIL PRESS, and AUX OIL PRESS indicating lights on the MAINTENANCE  PANEL,  alert  the  crew  to  impending transmission lubrication problems. The cautions operate independently of the pressure and temperature indica- tors on the center instrument panel. a. XMSN OIL HOT Caution.  It illuminates when the main oil temperature in the sump of the forward, aft and reservoir of the combining (mix) or either engine trans- mission exceeds 140_C. The hot transmission is identi- fied by the oil temperature selector switch and indicator and the TRANSMISSION OVERTEMP magnetic indica- tors on the MAINTENANCE PANEL. b. XMSN OIL PRESS Caution.  It illuminates when main oil pressure drops below 20 psi in any transmission or aft rotor shaft pressure drop below 10 psi. The low- pressure system is identified by the transmission oil pres- sure selector switch and indictors on the center instru- ment panel and the TRANSMISSION MAIN OIL PRESS indicating lights on the MAINTENANCE PANEL. If the XMSN OIL PRESS caution capsule illuminates and the affected transmission cannot be determined using the selector switch, the condition may be caused by loss of aft rotor shaft oil pressure. Low oil pressure at the aft rotor shaft is indicated by the illumination of the TRANSMIS- SION AFT SHAFT MAIN OIL PRESS indicating light on the MAINTENANCE PANEL. c. XMSN AUX OIL PRESS Caution.  It is activated by individual aux oil switches and illuminates when auxil- iary oil pressure drops  below 20  psi in the fwd or aft transmission and 10 psi in the combining (mix) transmis- sion. The transmission with the low pressure is identified by a lit TRANSMISSION AUX OIL PRESS indicating light on the MAINTENANCE PANEL. d. 712  NO. 1 or NO. 2 ENG XMSN HOT,   714A ENG 1 XMSN HOT or ENG 2 XMSN HOT Caution.  They illuminate if oil temperature in either engine transmission exceeds about 190_C. The capsules are activated by a thermoswitch in each engine transmission. The thermo- switch monitors oil temperature in the transmission, not in the reservoir. It is part of a chip detector and tempera- ture assembly in each engine transmission. 2-7-11.  Transmission Chip Detectors. Chip detectors are installed in all transmission and aft rotor shaft thrust bearing lubrication systems. All trans- mission chip detectors, except those in the engine trans- mission, are connected to the XMSN CHIP DET caution capsule on the master caution panel. Engine transmis- sion chip detectors are connected to the corresponding 712  NO. 1 or NO. 2 ENG CHIP DET,  714A   ENG 1 or ENG 2 CHIP DET caution capsules. All transmissions and aft rotor shaft chip detectors are also connected to the TRANSMISSION CHIP DETEC- TOR magnetic indicators on the MAINTENANCE PAN- EL. When a chip detector is bridged by ferrous particles, the XMSN CHIP DET, or the   712  NO. 1 and/or NO. 2 ENG CHIP DET,  714A  ENG 1 and/or ENG 2 CHIP DET caution capsule illuminates. At the same time, the corre- sponding TRANSMISSION CHIP DETECTOR indicator on the MAINTENANCE PANEL will trip and change from an  all-black  indication  to  a  black-and-white  indication, identifying the transmission.