TRUCK SERVICE MANUAL
TRANSMISSION
HT 700D SERIES TRANSMISSIONS
Para 3-13/3-14
event of brake failure or inadequate blocking. Do not
(4) If high engine speed is noted, refer to the
maintain the stalled condition longer than 30 seconds
troubleshooting chart in paragraph 3-19.
due to rapid heating of the transmission oil. With the
transmission in neutral, run the engine at 1200 to 1500
3-14. PRESERVATION AND STORAGE
rpm for 2 minutes to cool the oil between tests. Do not
allow the converter-out temperature to exceed 3000F
Selection.
When
a. Preservative
Method
(1490C). Keep close check to prevent the engine cooling
transmissions are to be stored or remain inactive for
system from overheating.
extended periods of time, specific preservative methods
a re recommended to prevent rust and corrosion
b. Procedure
damage. The length of storage will usually determine the
preservative method to be used. Various methods are
CAUTION
described below.
Do not attempt to stall test the transmission in reverse.
The extremely high torque produced may damage the
b. Storage, New Units. New units contain
preservative oil when shipped, and can be safely stored
transmission and/or the vehicle drive line.
for 6 weeks without further treatment.
(1) Connect a tachometer of known accuracy to the
engine. Stall torque converter by locking the transmission
c. Storage, Month to 6 Weeks
output (putting the transmission in gear) and accelerating
(1) The following procedures will prepare a
the engine to full throttle. Note the maximum rpm the
transmission for a month to 6 weeks storage, depending
engine will attain. The speed attained is then compared
on the environment.
to the speed specified, by the vehicle manufacturer as
(2) Drain the oil as described in paragraph 3-7. Re
normal for those conditions. This information (stall
move the transmission oil filter(s).
(3) Install the new filter(s), gasket, oil pan, and fill
speed) may be obtained from your equipment dealer or
tube.
distributor. An engine speed above or below the specified
(4) Fill the unit to operating level with any
range may indicate a malfunction in the engine or
commercial preservative oil which meets US Military
transmission.
specifications MIL-L-21260, Grade 1, to latest
NOTE
specifications.
(5) Operate the unit for at least 5 minutes in neutral
Engine power will decrease with an increase in elevation
at 1500 rpm. Shift the transmission slowly through all
(altitude), the decrease becoming more pronounced at
selector positions to thoroughly distribute the oil. Then,
greater elevation. This will result in a lower engine speed
shift to a forward range and stall the transmission output
under converter-stall conditions.
until an oil temperature of 225F (1070C) is obtained.
(2) After making allowances for elevation, a low
CAUTION
engine speed may indicate the engine is not delivering
Do not allow temperature to exceed 225F (1070C).
full power. Refer to the engine service manual for engine
(6) Stop the engine. As soon as the unit is
repair information.
cool enough to touch, seal all opening sand breather with
moisture-proof tape.
(3) If low engine speed persists after the engine is
tuned, refer to the troubleshooting procedures and chart
in paragraph 3-19 below.
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