MIL-DTL-62461E(AT)
4.4.5 Operating environment requirements verifications. Complete and pass each of the
tests as specified in 4.4.5.1 through 4.4.5.4.
4.4.5.1 High temperature. The transmission, without external load and with provisions
for oil cooling, shall be tested as follows:
a. Place the transmission in a test chamber for not less than 6 hours at a temperature
of 120°F (49°C).
b. Raise the chamber temperature to 160°F (71°C) within a time period of 1 hour and
maintain at that temperature for an additional 4 hours.
c. Lower the chamber temperature to 120°F (49°C) within 1 hour.
d. Repeat steps a, b, and c two additional times (making a total of three 12 hour
cycles).
e. Adjust the chamber temperature to the highest operating temperature under which
the transmission is designed to operate and maintain until temperature stabilization
of the transmission is reached.
f. Operate the transmission until it is stabilized through all gear ranges.
g. Return the transmission, nonoperating, to standard ambient conditions and
stabilize.
h. There shall be no evidence of damage or malfunction during or after the test.
4.4.5.2 Low temperature. The transmission, without external load and with provisions
for oil cooling, shall be tested as follows:
a. Place the transmission in a test chamber for not less than 24 hours at a temperature
of -26°F (-32°C).
b. Raise the chamber temperature to -20°F (-30°C) and maintain until temperature
stabilization of the transmission is reached.
c. Operate the transmission until it is stabilized through all gear ranges.
d. Return the transmission, nonoperating, to standard ambient conditions and
stabilize.
e. The rate of temperature change (steps a, b, and d) may be the maximum attainable
by the chamber but shall not be greater than 18°F (10°C) per minute.
f. There shall be no evidence of damage or malfunction during or after the test.
4.4.5.3 Leak decay. The transmission, without oil, shall be submerged in water to a depth
sufficient to completely cover the assembly for at least 5 minutes. The internal air pressure shall
be 3-5 pounds per square inch (psi) (21-35 kilopascals (kPa)). The transmission shall be checked
for leaks. No air bubbles shall be permitted.
4.4.5.4 Steam and waterjet cleaning. All transmission interface openings shall be sealed
and the transmission shall be steam cleaned using high pressure steam and cleaner. After steam
cleaning the transmission shall be waterjet washed and subsequently checked for any deterioration
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