MITSUBISHI ECLIPSE 1990 Service Manual

AUTOMATIC TRANSAXLE - Transaxle Control21-79
70 rear clutch via
rear clutch exhaustvalve
Frommanual valveOrifice
Line pressure From pressure
from manual
control valve
valve
175024
valveFrom manual
From pressure
valvecontrol valve175024Shift from “N” to
“D” .
When the manual valve is shifted from the “N” to the
“D”range position, the following sequence of events occur.
(1) The line pressure from the manual valve is distributed
through the No. 5 line to the NO. 5, NO. 5d and No. 5e lines ofthe N-D control
VdVe.
(2) The No.5 port is closed at this stage by the N-D control
valve.(3) There is a chamber with a check ball on the No.
5d line. Asthe check ball is held pressed against the downstream
opening of the chamber by the line pressure, the line
pressure passes through the
No.Se line, which has an
orifice provided.
(4 The line pressure, after being attenuated by the orifice, is
directed to the No.5c line.
(5) Meanwhile, the pressure from the pressure control valve
which has been regulated by the pressure control solenoid
valve is supplied through the No. 10 line.
(6) There is an orifice in the No. 10 line and the pressure which
is attenuated by passing through this orifice flows into the
No.
5c line.
(7) The No. 5c line pressure is directed to the rear clutch via therear clutch exhaust valve.
(8) If the rear clutch completes engagement, the duty setting
of the pressure control solenoid valve becomes zero
percent, increasing the pressure to the line pressure level.
(9) The line pressure thus established in the No.5c line works
on the N-D control valve to move it towards the right. This
rightward movement is’ caused by the difference in area to
which pressure is applied between the two lands.
(lO)The above movement of the N-D control valve opens theNo.5 port, and through the port, the line pressure estab-
lished in the No. 5 line flows into the No.
5c line and then is
directed to the rear clutch via the rear clutch exhaust valve.

21-80AUTOMATIC TRANSAXLE - Transaxle Control
VALVE WITH ORIFICE
When
oressureis releasedWhen pressure
-is applredTo rear clutch
via rear clutch
exhaust valveTo low-reverse brake
i
Ltne pressure1
- 2 shiftvalve
Ex
1750242If the accelerator pedal is depressed ‘immediately
after shifting the select lever from
“N” to “D”, the
rear clutch engages directly and the vehicle moves
in
1st gear. Due to the arrangement of the hydraulic
circuit, in thjs case, the hydraulic pressure is actuallydirected to both the rear clutch and the low-reverse
brake, thus dividing the quantity of the distributed
fluid. This in turn can cause a delay in clutchengagement when the fluid temperature is high. To
prevent this, a special valve is provided in the
low-reverse brake circuit. This valve has an orifice
which restricts flow of fluid when the pressure is
directed to the low-reverse brake but has no flow
restriction effect when the low-reverse brake press-
ure is released, thus preventing sluggish release of
the brake.

AUTOMATIC TRANSAXLE - Transaxle Control21-81
3 CLUTCH VALVE
To front clutch
.To end clutch
To kickdown
servo release
Shift
control
solenoid
valve
- BShift control
solenoid valve
-A
II
J
ExIPlug
End clutch valve
‘11 E”
Line pressure
1750243End clutch valve controls the timing for supplying hydraulic
pressure to the end clutch.In 2nd Gear
(1) When hydraulic pressure is not being directed to the end
clutch valve, it is held pushed to the left by the spring force
(see above figure).
(2) If the
2nd pressure from the shift control valve is directed
to the end clutch valve via the No.6 line, the end clutch
valve is forced toward the right.
,nd Gear
Lrom manualvalveTo end,&tch.
2ndpressurepressure
I17501i

21-82AUTOMATIC TRANSAXLE - Transaxle Control
valve
A
2nd3rdpressure pressure175011:To shift
control
valve#3
land
2nd3rdpressure pressure
175011~LlUpshift from
2nd to 3rd Gear\(1) When the shift control valve comes into
3rd gear position
and the
3rd pressure is established, the pressure is
directed to the No.7 port of the end clutch valve through
the No.7 line. In this instance, the
3rd pressure is blocked
ahead by the end clutch valve and the check ball.
(2) If a shift to the
3rd gear is initiated, the pressrue begins to
be directed from the
2-3/4-3 shift valve to the front clutch
and the release side chamber of kickdown servo cylinder.
The same pressure also is directed to the chamber at the
right end of the end clutch valve through the No. 12 line.
During the shift to the
3rd gear, the pressure in the No. 12
line is regulated by the pressure control valve to a level
lower than the line pressure so that the No. 12 line pressureis not high enough to force the end clutch valve toward the
left.(3) Once the front clutch has been engaged and the kickdown
brake released, the No. 12 line pressure is raised to a level .
equivalent to the line pressure.
This means that the pressures at both ends of the end
j
clutch valve (or No. 6 line pressure and No. 12 line pressure)[are at the same level. However, as the area of the
#3 land
to which pressure is applied is larger than that of the
# 1
land of the end clutch valve, the valve is pushed to left, thusopening the No.
18 port. This allows the 3rd pressure (line
pressure) already established in the No. 7 line to be directedto the end clutch through
the..No.7 port. The end clutch is
now engaged.
Downshift from
3rd to 2nd Gear
(1) Both front clutch pressure and kickdown servo release
pressure are released, and therefore, the pressure in
theend clutch valve right end chamber is also released.
--
(2) This results in a rightward movement of the end clutclvalve by the
2nd pressure working on its left end, closingthe
No.7 port and releasing the end clutch pressurethrough the No.8 port. Now the end clutch is released,
I

is-7--
1
AUTOMATIC TRANSAXLE
- Transaxle Control21-83I4th
pressureTo end To
2-314-3clutch shift valve
1it2nd3rdpressure
pressure
In 4th Gear
(1) In 4th gear, the front clutch pressure and the kickdown
release pressure are ‘both released, and therefore, the
pressure at the No. 12 port is also released.
(2) Once the pressure starts being released through the No. 12port, the pressure acting on the right end of the plug
(pressure admitted through the No. 18 port) pushes the endclutch valve to the left and holds it in the
same position as
that it has in 3rd gear.
This holds the end clutch engaged.
(3) The
No.8 circuit provides a fail-safe feature which, in the
event of impossibility of
line pressure transaxle to the
No. 18 line from the No.7 line due to improper movementof the end clutch valve by some reasons, allows the line
pressure to have an alternate passage (through the No.8line) to the No. 18 line during
4th gear.

--
I121-84
AUTOMATIC TRANSAXLE - Transaxle Control
jREAR CLUTCH EXHAUST VALVE
j,
iIi
i
cto front
To rearclutchclutchTo kickdown
servo release side
2-3/4-3shift valve
Shift control
solenoid valve
- Aa
Ex
5a
Shift
controlsolenoid
valve
- B
- From l-2shift valve
I
ExThe valve is actuated by the line pressure controlled
by the shift control valve to release the oil pressure
of the rear clutch when shifting
iS performed from3rd to 4th gear. The valve also controls the timing ofthe oil pressure to be supplied to the rear
clutchwhen shifting is performed from 4th to 3rd
gear.preventing shocks from occurring.

AUTOMATIC TRANSAXLE - Transaxle Control21-85
I o 2-314-3shift valveFrom rear
clutch
11 1From N-Dcontrol valve
FromshiftTo manualcontrolvalve
valve
(4thoressure)175011‘
1
>rn 2-314-3jnift valveTCPUE’Check t
I
To shiftcontrol To manualFrom N-Dmntmlvalve
”.,,l”l
(4thvalve
valvepressure)
--
II1111
”
E,Upshift from
3rd to 4th Gear
(1) When the 4th pressure from the shift control valve is
directed to the rear clutch exhaust valve through the No.8
line, it pushes the elements “A” and
“B” of the rear clutch
exhaust valve to the right.
(2) The element “B” of the rear clutch exhaust valve that has
been moved towards the right closes the
No.5~ line port.
This prevents the line pressure coming from the N-D
control valve from being directed to the rear clutch.
(3) The line pressure supplied to the rear clutch is discharged
from the No. 15 line through the No.20 and No.20a lines.
This releases the rear clutch.
Downshift from 4th to
3rd Gear
(1) If the
4th pressure from the shift control valve is dis-
charged, the element “A” of the rear clutch exhaust valve
is pushed to the left under the line pressure established in
the
No.5~ line. This line pressure is directed to the rear
clutch via the No.20 line, No.
20a line, and then No. 15 line.
In one of the passages connecting the No.20 line with the
No. 20a line, there is a check ball and in the other there is anorifice. When one passage is closed by the check ball, the
fluid flows through the other passage with an orifice, which
slows down the fluid flow speed, permitting gradual
transaxle of pressure to the No.20a line to create condi-
tions ready for the rear clutch to operate.
(2) When the
2-3/4-3 shift valve operates and the hydraulic
pressure acts on the front clutch and the release side
chamber of kickdown servo cylinder, the pressure is
directed through the No. 12 line to the right end of the
element
“8” of the clutch exhaust valve.
Combined with the spring force, this pressure pushes the
element “B” of the valve to the left. This allows the high
line pressure in the
No.5~ line to be directly transmitted to
the rear clutch through the No. 15 line.

21-86AUTOMATIC TRANSAXLE - Transaxle Control
SOLENOID VALVEThere are four solenoid valves installed on the valve
bob,,they are activated, as explained previously, by commands from
the transaxle control unit.
Terminal 1
Pressure control solenoid valve
2Damper clutch control solenoid valve
3Shift control solenoid valve “A”
I~-- I4Shift control solenoid valve “6”1
GroundGround
w--------%Pressure control
solenoid valvel
rI
IkI!iiLDamper
clutch
control
solenoid
valve
IShift
control
solenoidivalve-A
;
IShift
control
solenoid
ivalve-B
Connector17wo35

AUTOMATIC TRANSAXLE - ~kmucle ControlHWBRAULIC
ClRCUlT
S.XTOR LEVER IN “N”Torque-converterKickdown servo
FrontRearu)w-reverse =.I 1~
clutchclutchbrakeclutch
r-m I
-amper clutchIhOlJenoid valve
Oil -filter,
IIShi LroI3,
Lii PressureTorque-converter pressureand
lubriition oil pressureReducing pressurePump suction pressure
Lii Pressure(control pressure)
PCSV control pressureDamper clutch pressure
DCCSV control pressure
I1760224
A

21-88AUTOMATIC TRANSAXLE - Transaxle ControlTSELECTOR LEVER IN “P”
icTorque-convertersolenoid valve
I IncFoque-converter
,xmtrol valveIT=7
IIcontrolsolenoidII.- L. .- mlvi-we 0
II
PRNDPLPressure
7ntfol
wpan J
= Line Pressurem Pump suction pressureDamper clutch pressureTorque-converter pressureand lubrication oil
pressurem Line Pressure(control pressure)m DCCSV control prasswe
Reducing pressurem PCSV control pressureI
1750245
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