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Automatic transmission-37
power transmission Automatic 3rd-Gear and manual 3rd-Gear
In automatic and manual 3rd-Gear, the drive of transmission reaches the front cylinder through the input shaft. In this condition,
the operating principle of the transmission is shown as follows:
The engagement of clutch C2 drives the front sun gear
The engagement of clutch C1 drives the planetary gear carrier
The forward central gear and planetary gear carrier rotate in the same speed clockwise. So, there is not relative motion
between the forward central gear and planetary gear.
The gear ring and output shaft rotate in the speed of output shaft, and makes the moves forwardly.
The engagement of clutch C4 is through the 3-4 one-way clutch (OWC) and make the engine to provide the brake force
in overspeed.
Control:
In stable status, the status of solenoid valve and valve is shown as follows:
The solenoid valve S1 is powered off; Solenoid valve S2 is powered off
When the solenoid valve S1 and S2 is powered off, 2-3 and 3-4 shift valve are kept in 3rd-Gear position through the line
pressure 500.
1-2 Gear shifting valve is kept in 3rd-Gear position by the oil pressure of S1 and S2.
The (line pressure)oil form the 1-2 Gear shifting valve flows into the brake belt combination regulating valve directly and
flows into the 2-3 Gear shifting valve.
The brake belt combination regulating valve provides the 2nd-Gear oil (controlled by the product of line pressure and valve)
to the brake belt feed loop(BAF).
The brake belt feed loop directly provides the oil to:
External combination part of front servo
When the transmission is shifted to 1st-Gear, the 1-2 Gear shifting valve provides the oil drainage port.
When the transmission is in 4th –Gear position, it will use the 3-4 Gear shifting valve.
The 2nd-Gear oil of 2-3 Gear shifting valve flows into the 3rd-gear loop directly .
The 3rd-Gear oil from the 2-3 Gear shifting valve flows into the clutch combination regulating valve and sequence valve of
4-3 Gear directly.
The clutch combination regulating valve provides the oil of clutch attachment feed loop (controlled by the product of line
pressure of 500 and valve ratio) (CAF).
CAF directly provides the oil to :
clutch C1
Sequence valve of 4-3 Gear
In 4-3 Gear shifting valve, the CAF oil is changed to the release fluid of B1 (B1R-F), it cause the closing of brake belt 1
through the 3-4 Gear shifting valve to spring bottom of 4-3 gear sequence valve and release side of front servo.
The drive force (line pressure ) is sent to the clutch C4 through the 3-4 Gear shifting valve to engage the clutch C4 .
Refer to Figure 5.6 and Table 5.7.
Table 5.7
Table of participating condition of each unit in automatic and manual 3rd –Gear
Clutch
Name of participation unit
Automatic and manual
3
rd –Gear
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Automatic transmission-38
Figure 5.6 Automatic 3
rd –Gear-manual 3
rd-gear
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Automatic transmission-39
Power transmission locking of automatic and manual 3rd-Gear
When the automatic 3rd-Gear and manual 3rd-Gear is locked, the drive of transmission is basically same as that in automatic 3rd-
Gear. But it provide the variable torque drive without slide for the application of torque converter locking clutch.
Control:
The control for the automatic 3
rd-Gear locking and manual 3rd-Gear locking is basically same as that for automatic 3rd –Gear. But
it should be described additionally that the automatic 3
rd-Gear and manual 3rd-gear locking needs the action for variable torque
clutch loop by solenoid valve S7.
When the solenoid valve S7 is opened, the variable torque clutch control valve is closed and allow the oil feed of S7 loop pass
through the solenoid valve S7 to drainage port. It makes the control valve moves to the clutch combination position.
The loop oil from the line 500 flows into the combination part of variable torque clutch through the converter clutch control
valve through the action of variable torque clutch control valve.
The variable torque clutch release oil is drained from the variable torque clutch control valve.
The torque converter loop oil flows into the oil cooler and lubrication loop through the variable clutch control valve.
Refer to Figure 5.7 and table 5.8.
Table 5.8Participating condition of each unit in automatic and manual 3rd-Gear locking
Automatic 3rd-Gear locking and
manual 3
rd-gear locking
Name of participation unit
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Automatic transmission-40
Figure 5.7 Automatic 3
rd –Gear locking and manual 3
rd-Gear locking
Page 117 of 425

Automatic transmission-41
In automatic 4th-Gear (overspeed gear), the drive of transmission is sent to the front clutch cylinder through the input shaft. The
operation principle of each function assembly of transmission is shown as follows:
The engagement of clutch C1 drives the planetary gear carrier rotates in clockwise rotation.
The engagement of B1 brake belt makes the reverse sun gear to stop.
When the planetary gear carrier rotates, the long planetary gear rotates around the static reverse sun gear, at the same time, it
rotates around its axial line to drive the gear ring and output shaft to generate the forward movement in the speed higher than
that of input shaft (i.e. overspeed) clockwise.
The forward central gear rotates in the speed higher than input shaft and is more than the speed when 3-4 one-way clutch
(OWC) is engaged.
The engagement of clutch C2 is used to reduce the speed difference generated by 3-4 one-way clutch (OWC).
Control:
In the stable status, the status of solenoid valve and valve is shown as follows:
The solenoid valve S1 is powered on ; S2 is powered off.
When the solenoid valve S1 is powered on, the small end of 3-4 shift valve is in 4th-Gear position for the pressure of line 500.
When the solenoid valve S2 is powered off, the large opening of 2-3 shifting valve is in 4th- Gear position for the pressure of
line 500.
The 1-2 Gear shifting valve is kept in 4th-Gear position for the pressure of S2 oil loop.
The 2nd-Gear loop oil (line pressure) from the 1-2 shift valve flows into the brake belt combination regulating valve and 2-3
shift valve directly.
The brake belt combination regulating valve provides the 2nd-Gear loop oil for the brake belt attachment loop (BAF) (adjusted
by product of line pressure and valve ratio)
The brake belt combination lip oil is directly supplied to:
External combination part of front servo
Enter into the internal combination part of front servo piston through 3-4 shift valve
The 1st-Gear-2 switch valve provides a oil-drain port when the transmission is switched to 1st-Gear.
The 2nd-Gear loop oil in 2-3shift valve flows into the 3rd-Gear loop directly.
The 3rd-Gear loop oil from the 2-3 shift valve flows into the clutch combination regulating valve and 4th-Gear-3 sequence
valve directly
The clutch combination regulator valve supplies the oil for the clutch combination loop (CAF) (Regulated by the product of
line pressure and valve rate)
CAF oil is directly supplied to:
clutch C1
4th-Gear-3 sequence valve
The drive oil(line pressure) form the manual-operated valve forces the engagement of clutch C2
Refer to Figure 5.8 and Table 5.9.
Table 5.9
Participating condition of each unit in automatic 4th –Gear (overspeed Gear)
clutch
Name of participation unit
Automatic 4
th-Gear
(overspeed Gear)
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Automatic transmission-42
Figure 5.8 Automatic 4
th-Gear (overspeed Gear)
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Automatic transmission-43
Power transmissionAutomatic 4th-Gear locking
In automatic 4th –gear locking, the drive of transmission is same as that in automatic 4th –gear basically. But for the application of
variable torque locking clutch, it provides the variable torque drive without slide.
Control:
The automatic 4th –Gear locking is same as that in automatic 4th-Gear basically. But it should be described that when the automatic
4
th-Gear is locked, it has the action for variable torque loop by solenoid valve S7.
When the solenoid valve S7 is opened, the variable torque clutch control valve is closed and allow the S7 loop oil flows to the
drainage port through the solenoid valve S7, then control the valve to move to the clutch engagement position.
The line pressure loop regulating oil from the torque converter clutch regulating valve flows into the combination side of torque
converter clutch directly.
The release oil of torque converter clutch is drained from the control valve of torque converter clutch..
The torque converter loop oil flows into the oil cooler and lubrication loop directly through the control valve of torque
converter clutch..
Refer to Figure 5.9 and Table 5.10.
Table 5.10
The participating condition of each unit in automatic 4th-gear locking
Clutch
Name of participation unit
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Automatic transmission-44
Figure 5.9 Automatic 4th –Gear locking