TRUCK SERVICE MANUAL
TRANSMISSION
HT 700D SERIES TRANSMISSIONS
on transmissions matched to engines having governed
Para 3-11/3-13
speeds from 2100 to 2700 rpm.
NOTE
(2) The actual adjustment procedures are as
If more than one shift signal valve spring requires
outlined in d, above. However, the base for checks and
adjustment, it may be necessary to adjust the spring
adjustments is output shaft speeds instead of engine
compression on the modulator valve one position in the
governed speed. Individual output shaft speed ranges
same directionas adjustment for signal valves. If all
are given for each shift.
upshift points are either too high or too low, by
approximately the same amount, only the modulator
valve should be adjusted.
3-12. EXTERNAL LINES AND OIL COOLER
(5) Refer to Sections 5, 6 and 7 for procedures
a. External Lines
covering removal and replacement of affected
components. Spring charts are at the end of Section 8
(1) Inspect for loose or leaking connections,
immediately preceding foldouts.
worn or damaged hoses, tubing and loose fastenings.
e. Alternate Method Using Speedometer Readings
(2) Examine the radiator coolant for traces of
transmission oil. This condition indicates a faulty heat
exchanger.
(1) When a tachometer is not available for checking
shift points, the vehicle speedometer can be used.
b. Oil Cooler. Transmission operation at abnormally
Proceed as outlined in (2) through (4) below.
high temperatures can cause clogging of the oil cooler as
well as transmission failure. It is suggested the oil cooler
(2) Check and record the road speed of the vehicle
system be thoroughly cleaned after each major or minor
at which lockup occurs during operation in 1-hold (refer
rebuild (para 3-8d). Failure to do so may cause poor
to (3), above). Also check and record the top speeds that
performance, overheating and transmission damage. For
can be attained while operating in 1-2, 2-3 and 3-4.
recommendations for cleaning or flushing the oil cooler,
see the vehicle service manual.
(3) For checking the shift points, place the selector
at 1-5 so that all automatic shifts can occur Drive the
3-13. TRANSMISSION STALL TEST
vehicle at full throttle from a standing start until the 4-5
upshift occurs. Record the road speed at which each
a. Purpose. A stall test may be conduct-d when the
upshift occurs.
power package (engine, transmission combined) is not
performing satisfactorily. The purpose of the test is to
(4) Compare the upshift speeds with the speeds
determine whether the transmission or the engine is the
recorded in (2), above. The 1-2 shift should occur at
malfunctioning component.
approximately two mph below the speed recorded for
lockup engagement. All other upshifts should occur
CAUTION
approximately two mph below the top speeds recorded in
When conducting a converter stall test, the
(2), above.
vehicle must be positively prevented from
moving. Both the parking and service brakes
f. Calibration by Test Stand Method
must be applied and, if necessary, the
(1) The table below provides detailed information
vehicle should be blocked to prevent
required for adjusting shift points
movement forward or in reverse. Warn
personnel to keep clear of the vehicle and its
travel path in the
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