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 TM 9-8000
CHAPTER 24
CROSS-DRIVE TRANSMISSION
Section I. FUNCTION
ing mechanism, braking mechanism, and hydraulically
24-1. General. Several models of cross-drive
operated clutches. The brakes are foot operated. The
transmissions are in use, differing in some details from
forward- and reverse-speed ranges and the steering are
each other. All, however, operate in a similar manner.
selected and hydraulically controlled from the driver's
This type of transmission is a combination transmission
compartment. The transmission mounts crosswise in the
and steering unit for use on tracked vehicles.
vehicle and drives the two tracks through two flanges:
the right output shaft flange and the left output shaft
24-2. Functions. The cross-drive transmission provides
flange (right and left facing toward the front of the
hydraulic drive through a torque converter and contains
vehicle).
the planetary gearing, steer-
Section II. CONSTRUCTION AND OPERATION
turbine vanes at less of an angle and it begins to strike
24-3. General. There are several models of cross-drive
the back faces of the first stator vanes. The first stator
transmissions. In general, this discussion will apply to all
thus begins to free wheel. In effect, it is simply moving
models of cross-drive transmissions except for the
out of the way. The second stator, however, still is
X1100-3B unit, which is covered in chapter 25.
needed to change the direction of oil flow.
Reference should be made to the applicable technical
manual whenever a detailed study of a particular cross-
c. In the coupling phase (C, fig. 24-3), the turbine
drive transmission is made. Figure 24-1 shows an
and pump are revolving at nearly the same speed. The
external view of a cross-drive transmission, while figure
assembly acts like a fluid coupling. Both stators free
wheel. Details of torque converter operation are found in
paragraph 21-7.
24-4. Torque Converter. The torque converter is a
four-element (or four-member) converter similar to units
d. The converter contains a lockup clutch that
described in paragraph 21-7. Note the location of the
engages automatically when the transmission speed
converter units in figure 24-3. The converter contains a
reaches a certain value. As this happens, the pump and
pump and turbine plus two stators mounted on the
turbine are locked together and rotate as a single unit.
converter ground sleeve by freewheeling clutches.
Power, therefore, is transmitted mechanically through the
Converter action is shown in figure 24-3. The pump
converter and no speed reduction or torque multiplication
drives the turbine through the medium of oil as described
occurs.
in paragraph 21-8. The stators reverse the direction of oil
flow into a helping direction as it comes off the turbine
24-5. Planetary Gearing In Gear Ranges.
vanes. Action is described below.
a. In the first converter phase (A, fig. 24-3), the
a. General. The cross-drive transmission contains
stators are locked and the oil flow direction is reversed
four planetary gear systems: the low- range planetary,
by the action of the two stators. The oil passes from the
the reverse-range planetary, and the two output
pump vanes, circulates through the turbine, two stators,
planetaries. The low- and reverse-range planetaries are
and back to the pump.
located in the right housing of the transmission (fig. 24-
2). At each end of the cross-drive shaft is an output
b. In the second converter phase (B, fig. 24-3), the
planetary that drives the output flanges. All the
turbine has picked up speed and there is less torque
planetaries are similar, having four planet pinions and the
The
oil
leaves
the
usual sun gear and internal gear (also called ring
24-1
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