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.
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.
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.
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.
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.