TRUCK SERVICE MANUAL
TRANSMISSION
HT 700D SERIES TRANSMISSIONS
Para 2-19/2-23
assembly is bolted to the bottom of the transmission
case, which is channeled to direct the flow of oil between
2-19. SPEEDOMETER DRIVE
the valve body and clutches, and other components.
a. Description (A, foldout 16)
b. Operation. Refer to paragraph 2-26, below, for
operation of the control valve body assembly.
(1) The speedometer drive consists of drive
gear 24 and driven gear bushing 15.
2-22. LOW SHIFT AND TRIMMER VALVES
(2) Drive gear 24 is a worm gear with a right
a. Description (A, foldout 17). Low shift valve body
hand helix. The gear is concentric with the output shaft
assembly 2 contains a relay valve, a shift valve, springs,
and has no key or drive splines. The drive gear is
pins and an adjusting ring. It is mounted on the bottom
clamped between rotating parts which, in turn, cause the
of the control valve assembly, and retained by bolt 1.
drive gear to rotate.
Mounted directly under the low shift valve body, is low-
trimmer valve body assembly 18. This body consists of
b. Operation (A, foldout 16).
When the
a valve, trimmer and retainer plugs, a spring, a valve
transmission output shaft rotates, drive gear 24 rotates.
stop and a pin. Six bolts (17), extending through both
Bushing 15 supports the driven gear (vehicle
valve bodies and the control valve assembly into the
furnished)within the rear cover. The driven gear rotates
transmission housing, retain the two bodies.
clockwise (as viewed at the cable connection in the rear
cover) during forward operation.
2-24. OIL PAN AND OIL FILTER
2-20. GOVERNOR
a. Description (A, foldout 14)
a. Description(A, foldout 16). Governor assembly
(1) Oil pan 30 is a pressed steel assembly
38 is a centrifugal (flyweight) governor which is driven by
that provides one opening for attaching a combination oil
output shaft 23 or 30. The governor is supported by a
filter and level gage tube, and another for draining the oil.
bore in rear cover 14 and pin 11, and retained in the rear
Earlier models did not provide a separate drain, and oil
cover by cover 42.
was drained by loosening the filler tube.
b. Operation (A, foldout 16).
Rotation of the
(2) Oil filter 25 is a box-like sheet metal frame
governor causes the governor valve (foldouts
5, ) to
with a perforated sheet metal reinforcement covered by a
travel within its bore. When the valve moves leftward,
fine-mesh screen across the bottom. Sump oil is drawn
governor pressure rises; when the valve moves
through the screen by the oil pump and directed into the
rightward governor pressure falls.
Thus, governor
hydraulic system. Screw 28 attaches the oil filter to the
pressure is proportional to transmission output speed.
bottom of the control valve body assembly.
Governor pressure, in combination with modulator
pressure (para 2-26h, below), provides the automatic
b. Function (A, foldout 14)
shifting in the transmission. (Refer also to para 2-26g, i,
L k,
below, for additional information about
(1) Oilpan30 holds the entire oil supply for the
automatic shift circuits.)
transmission and covers the control valve body
assemblies and oil filter.
2-21. CONTROL VALVE ASSEMBLY
a. Description (B, foldout 16). Control valve body
assembly 1 includes the various valves, springs and
other components which control the selection of ranges,
and the automatic shifting of gears. The valve body
685
