1990 MITSUBISHI ECLIPSE Service Manual

3rd GearAUTOMATIC TRANSAXLE
- Transaxle Control21-67
control unitShift control
solenoid
vail
ExII5a
PlugShift control valve
‘F$&‘- - 2nd pressure
wkh- 3rd pressure
Stopper
Line pressure
rolunit deactivates the shift
ves“A” and “B”.hift control solenoid valve “A”
ure to be applied to the No.5a
forces both right and left plugs
To N-D
control
To rearclutchvalve
1750234Deactivation of the shift control solenoid valve
“B”allows pressure to be directed to the shift control
valve through the No.5b port. This forces the shift
control valve to the right until it comes in contact
with the right plug. When the shift control valve is in
this position, the No.7 port is opened and the line
pressure is directed through the port to the
2-3/4-3 shift valve and the end clutch valve.
This pressure is called
“3rd pressure”.

__- _ - __ ----____. _ ., _.- -....21-684th GearAUTOMATIC TRANSAXLE
- Transaxle Control
solenoid valve “8”
4th pressure
Icontrol unit
2nd pressure
3rd pressure
Shift control
valviI!
iEx
To N-Dcontrol valve
To rearclutch
Lme pressure
1750233
The transaxle control unit activates the shift control
solenoid valve “A” and deactivates the shift control
solenoid valve
“B”.Activation of the shift control solenoid valve “A”
releases-the pressure at the No.5a ports, which in
turn releases the pressure acting on the plugs at the
right and left of the shift control valve.Deactivation of the shift control solenoid valve
“B”results in rightward movement of both the
shiftcontrol valve and the right plug by line
pressureapplied through the No.5b port until the valve
isblocked by the stopper. This rightward movemeni
of the shift control valve opens the No.8 port ant
the line pressure is directed to the rear clutcr
exhaust valve.
This pressure is called
“4th pressure”.

/gi--__ .--.-9
Reducingvalve
To kickdown
servo via 1 - 2
shift valveLine pressureAUTOMATIC TRANSAXLE
- Transaxle Control21-69
PRESSURE CONTROL VALVE, SOLENOID
-_ VALVE AND N-R CONTROL VALVE
: Pressure Control Valve
: This valve regulates the pressure supplied to each
clutch under the control of the pressure control
j.. solenoid<,A ,valve to eliminate shock at the time ofPressure Control Solenoid Valve
This valve has its duty controlled by the transaxlecontrol unit command. It changes an electric com-
mand to corresponding hydraulic pressure.
N-R Control Valve
This valve prevents shock from occurring when the
select lever is shifted from “N” to
“R” (or from “P”
to
“R”) by controlling the oil pressure applied to the
low-reverse brake..Stopping (Selector lever in
“D” or “2”)
‘r) obtain adequate creep force when stopping, the
is kept in
2nd gear by directing the
to the rear clutch and the kickdown brake.
purpose, the pressure acting on the
=nnm is adjusted by the following method
- .--v.._ _ _ __ --Tan that it would be when driving in
..d gear.
he nrennurecontrol solenoid valve is duty control-
..s,. ..Jtransaxle control unit so that the No.231..a
pressure will be lower than the No.23
fine
bressure (reducing pressure). As a result, the
level lower ttlpressure control valve moves to the left under the
line pressure which acts on the difference in area
between the pressure control valve
# 1 and #2lands and the reducing pressure which acts on the
difference in area between the
#2 and #3 lands,
thus closing the No. 5 port by its
#2 land. This
reduces the No. 10 port pressure and the pressure
control valve is moved to the right by the spring
force. Through the No.5 port thus opened, the line
pressure is directed to the kickdown servo. The
pressure applied to the kickdown servo is adjusted
by the above-mentioned sequence.
-

. : j21-70AUTOMATIC TRANSAXLE
- Transaxle Control1st Gear (Selector Lever in “D” or
“2”)
Reducingvalve
D
1
Ex
4Line
’pressureTo low/reverse
brake via 1 - 2shift valveLine pressure
Ext 1
Reducing0 pressure
1 1 ExPressure control 1 b--,N-R control, ,
\ON (Chty 100%)
17soo96On command from the
transaxle control unit, the
duty of the pressure control solenoid valve is set at
100 percent (solenoid is constantly energized). This
reduces the No.23b line pressure to the minimum
level. As
4 result, the pressure control valve is
forced to
ihe left and the No. 5 port is closed, whichprevents pressure from being directed to . the
low-reverse brake via the
l-2 shift valve.
In very low vehicle speeds, however, the duty is set
to zero percent for the maximum pressure, which is
most practical for the control purpose.

AUTOMATIC TRANSAXLE - Transaxle Control21-71
‘ift (Selector Lever in “D” or “2”)
ReducingLine
ipressureTo kickdown servo
or from clutch
via3H
l-r
I
1 - 2 shift valve
Line pressure
Ext 1II ”i1
Reducingpressure
N-R control,,
II& Pressure control
solenoid valve
b-l
To ensure a smooth gear change when upshifting
:from 1st to 2nd, 2nd to 3rd. etc., the transaxle
lcontrol unit controls the duty of the pressure control
z$olenoid valve in order to regulate the control‘pressure established in the
#23b line which gov-
‘ems the operationof the pressure control valve. The
Jlne pressure that flows from the No.5 port to the
No. 10 port is regulated in this way.
-
i& all upshifts are controlied in a similar manner. the
icontrol for the upshift from 1st to 2nd gear will be
explained as an example.
The state of the hydraulic line in the
1st gear
condition is as mentioned on the previous page.
Ifthe transaxle control unit gives order that an upshift
from the
1st to the 2nd gear be initiated and the
duty of the pressure control solenoid valve
is‘usted accordingly, the No.23b line Pressure
is
-.dught higher than it is. in 1st gear. Then. the
pressure control valve moves to the right, opening
the No.5 port. Through the
No.5 port thus opened.
the line pressure from the No. 10 port is directed to
the kickdown servo via the l-2 shift valve. When
the line pressure is applied between the
# 1 and # 2
lands. of the rxessure control valve, the pressureDuty control
+OFF
1750097
effectively acts on an area equivalent to the differ-
ence in area between these two lands, and pushes
the valve to the left; the No. 5 port is closed by the
#2 land.
When the No. 5 port is closed, the No. 10 port
pressure decreases and, as a result, the valve
moves to the right. opening the No.5 port. Through
the No.5 port thus opened, line pressure is intro-
duced. By this sequence, the pressure directed to
the kickdown servo through the No. 10 port is
controlled. The No. 10 pressure is controlled by the
duty of the pressure control solenoid valve. That is.
if the duty is increased, the No.23b line pressure
which pushes the pressure control valve to the right
decreases and this causes a reduced No. 10 port
pressure.When the
1st to 2nd upshift is completed. the
pressure control solenoid valve is deactivated. In
this state, the No.23b line pressure level is equiva-
lent to that of the No.23 line and, therefore, the
pressure control valve is held pushed all the way to
the right. allowing the No.5 port line pressure to be
applied directly to the kickdown servo through the
No. 10 port and thus the kickdown brake is applied.

21-72AUTOMATIC TRANSAXLE - Transaxle Control
_. --.
1st Gear (Selector Lever in “L”)
ReducingnLow-reverse brake
via 1
- 2 shift
valveLine pressure
Line
’pressureI1
Reducingpressure
N-R control , ,
vaive
16--.. -
1750090The low-reverse brake has the capacity that the
vehicle can be reversed at any point. Therefore, the
low-reverse brake operating pressure for the
“L”range is set to a level lower than that for
“I?” range.
This lower pressure is produced by reducing the line
pressure from the No. 5 port of the pressure controlvalve by a certain level before being delivered
frorthe No. 10 port to the low-reverse brake via the
1-lshift valve.
The method of regulation of pressure from the
No.:port to the No. 10 port is the same as that for
tht“Upshift” explained on the previous page.

AUTOMATIC TRANSAXLE - Transaxle Control21-73
‘elector Lever in “R”
Reducingvalve
ReducingTo low-reverse
OFF1750099
en the manual valve is shifted to the
“R” rangedirected to the low-reverse brake. Through this
ition, the pressure control solenoid valve func-pressure control, the shocks that would occur while
Ions under duty control from the transaxle controlshifting to reverse are minimized.
to reduce the reducing pressure in the No.23bOnce the low-reverse brake is engaged, the press-and to creaje another control. pressure in this
ure control solenoid valve is deenergized and normal
. The balance of forces established between thereducing pressure is reestablished in the No.23bntrol pressure and the force of the N-R controlline. Because this reestablished reducing pressure
Ivespring determines the degree that the No.9forces the N-R control valve toward the left, the line
e port will be open. The line pressure from thepressure passing through the No.9 port is applied
9 line is regulated by
passinq through the portdirectly to the low-reverse brake through the No. 16
ose opening has been adjusted and then isport and engages the brake with a strong pressure
force.

21-74AUTOMATIC TRANSAXLE - Transaxle Control
l-2 SHIFT VALVE
First SpeedTO low-reverse brake-Shift control(at “L” range)sorenotd valve “A’.4Shift control
l-2 shift
valve
ON !.IEXShift
coitrol
I/
EX1valve
From pressurecontrol valve
t(at “L” range)
Line pressureTo kickdown servo
l?zza.. -apply sidet
1750235
Second Speed
EX
” IIII2nd press.!iavalve
IFrom pressurecontrol valve
1750236The valve is actuated by the line pressure that has
been regulated by the shift control valve to change
the line pressure flow when .shifting is performed
between
1st and 2nd gears.
It also controls the hydraulic pressure passage to
the
low:-?everse brake when in the R (reverse) gear.
In
1st GearUpsh’ft from
1st to 2nd Gear
If the 2nd pressure from the shift control valve isdirected to the
l-2 shift valve through the No.6port, the pressure acts on the left end of the valve
causing it to move to the right, and the No. 11
poflcommunicating with the kickdown servo is opened
The line pressure coming from the pressure
controivalve through the No. 10 line is then directed to thekickdown servo via the No. 11 line.
In
2nd. 3rd and 4th gears, the 1-2 shift valve is
always held pushed to the right.
) ;‘I
I. 4The
1-2 shift valve is pushed to the left and held
there by the spring force when no pressure is
directed to the valve.
In the
“L” range, the line pressure from the
pressure control valve is directed to the low-reverse
brake by way of the No. 10 and No. 17 ports.
,i