MITSUBISHI ECLIPSE 1990 Service Manual

AUTOMATIC TRANSAXLE - Transaxle Mechanism21-27
/clutch plate-Piston
End clutchretainer
(“7Hydraulic
pressure
POWER FLOWEND CLUTCH
End clutch is of the multiple disc type and is installed at the rear
end of the input shaft. The clutch is actuated in the fourth gear
(overdrive) to transmit the power from the input shaft to the
planetary gear carrier.
Actually. the end clutch also operates during third gear, and thisis to maintain smooth up-shifting to fourth gear.
Number of clutch discs3Number of clutch plates
3Number of reaction plates
1
PistonO.D.mm (in.)124 (4.88)I
I.D.mm (in.)29 (1.14)J
End clutchEnd clutch
IInput shaftEnd clutch retainerEnd clutch shaft
Carrier
a

.-
I
21-28AUTOMATIC TRANSAXLE - Transaxle Mechanism
KICKDOWN BRAKE
/Kickdown band
r\\ IKickdown sleeve
- Kickdown servo
switch
;‘- Locknut
Apply pressure
(2nd pressure)
1 Release pre&re (3rd pressure)I,
/ --Anchor
1750219The kickdown brake is a band type brake; it is
piston and rod moves toward the left, tightening the
composed of a kickdown band, drum, kickdownbrake band to hold the kickdown drum. As a result,
servo, switch and anchor.the reverse sun gear (interlocked with the kickdown
When the
2nd pressure is admitted to the apply sidedrum) is held. This brake functions during 2nd gear
chamber of,kickdown servo cylinder, the kickdownand during overdrive.

ToThe kickdown servo switch detects the position of thekickdown piston just before the brake is applied, and sends the
signal to the transaxle control unit. Using this signal, the
transaxle control unit controls the 2nd pressure both before,
and
during application of the brake. In the initial control stage or
until just before the kickdown brake
is applied, a higher 2ndpressure is supplied to the kickdown servo SO that thekickdown piston can move quickly for
faSter response to thekickdown condition that has been initiated. In the second
control
stage or while the brake is being applied, the 2nd
1750394pressure
is regulated at an optimum level SO that the band is
tightened on the drum the proper amount
for good kickdown
“feeling.”AUTOMATIC TRANSAXLE
- Transaxle MechanismY$21-29
,
ilOLDING DRUM WITH KICKDOWN BRAKE

21-30AUTOMATIC TRANSAXLE - Transaxle Mechanism
LOW-REVERSE. BRAKECentersupport
Hydraulic pressure.
Piston1750221
Low-Reverse brake is of the multiple disc type and
is composed of a center support, disc, plates, and a
piston. The brake operates when the shift is in
1stgear in the “L” range or back gear. It fastens the
carrier in the planetary gear set. That is, the shafts ofthe long and short pinions are fastened.
HOLDING CARRIER WITH LOW-REVERSE BRAKE
rLow-Reverse brake
Low-Reverse brake

iAUTOMATIC TRANSAXLE
- Transaxle Mechanism
ONE-WAY CLUTCH
I
’
21-31
Long pinion(Planetary gear carrier)
CarrierInput
output
Held
stationary
sun gear
170207170320One-way clutch is of the sprag type and is
incorpo-rated between the pinion carrier and the center
support.
In
1st gear (D or 2 range), the long pinion rotates
clockwise as viewed in’the direction of arrow P. This
produces a force which has the tendency to cause
the carrier to rotate counterclockwise, but the
carrier is blocked from rotating in that direction by
the one-way clutch. As a result. the long pinion
transmits its force to the
annulus gear.
The carrier, which is coupled with the one-wayclutch outer race, is free to turn in clockwise
direction. In an engine braking condition under
which the
annulus gear is turned first. the carrier
turns clockwise freely and, therefore, the engine
braking effect is not obtained.
INumber of sprags26
Width of clutchmm (in.)18.3 (720)HOLDING CARRIER WITH ONE-WAY CLUTCH
P 0
On-y clutchI
\Carrierl7so223

21-32AUTOMATIC TRANSAXLE - Transaxle Mechanism
PLANETARY GEAR
-.., ‘~ ~,.~.“.,
Reverse sun gear\ParkIng sprag
Carrier\
I\
i
\
Outer race.-End clutch shaftLow/reverse brake’s hub
Short pmlon17502L
The planetary gear set incorporated in
thus transaxle
is of the Ravigne’aux-type, and consists of a forward
sun gear, a reverse sun gear, a short prnion. a long
pinion, a carrier to support both pinions, and an
annulus gear.
The reverse sun gear is connected to the front
clutch retainer via the
kickdown drum, while the
forward sun gear is connected to the rear
clutchhub.
The carrier is built in one unit with the low reverse
brake’s hub and the outer race of the one-way
clutch. The carrier is connected to the end clutch via
the end clutch shaft.
The
annulus gear, to which the output flange isconnected, conveys driving force to the transfer
drive gear installed on the output flange. And the
parking sprag is provided on the outer circumfer-
ence of the
annulus gear.
Number of forward sun gear teeth
Number of reverse sun gear teeth
2634
INumber of short pinron teethI22 1Number of long pinion -teeth
Number of
annulus gear teeth74 1c-’

AUTOMATIC TRANSAXLE - Transaxle Mechanism21-33
POWER FLOW
T GEAR (“D” and ‘2” ranges)
Short
DinionCarrier
IForward sun gear
IOne-way clutch
IAnn&s gear
Rear clutch
-1Long pinioniransfer
drive gear
, Idler gear
Transfer* driven gear
17!50057
rear clutch is actuated when the shift is in 1 st gear in the
“D”. “2” or “L” range, driving force is transmitted to the forward sun
gear which rotates in the clockwise direction.
ITherefore, torque is conveyed from the forward sun gear through the
short pinion (counterclockwise) and the long pinion (clockwise) to theannulus gear (clockwise) to achieve the reduction ratio of 1 st gear.
Since the long pinion’s shaft (that is, the carrier) tries to turn
/counterclockwise at this time, the one-way clutch prevents this to
provide for a sufficient amount of driving force to be transmitted to
.
the annulus gear.
,
This means that, because the carrier can turn clockwise, engine brakedoes not function when the shift is in
1 st gear in the “D” or the “2”
range.

_____--._- .21-34AUTOMATIC TRANSAXLE
- Transaxde Mechanism
1ST GEAR (“L” range)
Low/Reverse brake
Carrier
IShort pinion
I
Forward sungearAnnulus gear
ODeratina elements:&ear clkch. .--. _.-__.I*Low-Reverse brake
1
I>\\PRear clutchLong pinion
1750058When the shift is in
1st gear in the “L” range, the low reverse brake is
actuated to fasten the planetan/ gear carrier, so that the gear does not
turn in either direction.
.
This means that engine brake works when the shift is in 1 st gear inthe “L” range.
cNOTEThe power flow in
1 st gear in the “L” range is the same as it is in 1 st gear
in the “D” and “2” ranges.

2ND’ GEARAUTOMATIC
TRANSAXLE - Transaxle Mechanism21-35
Kickdown brake
I
Shon pinion
\Forward sun gear
1.//LT.//. , ,’ .‘,,i.:,;:.:‘.,.‘,\/
/
Annulus gearLong pinion
Rear clutch/Reverse sun gear
fharatinn damants:
-, IWI WUIUI IWickdown brakeI
.
c
Since the rear clutch and the kickdown brake are actuated when theshift is in
2nd gear in the “0” or the “2” range, driving force is
transmitted to the forward sun gear which rotates in the clockwise
direction,
Therefore, torque is conveyed from the forward sun gear through the
short and long pinions to the annulus gear, as in the case of 1 st gear.
--However, since the reverse sun gear is fastened by in the case of
2ndgear, the long pinion“walks” on the reverse sun gear in the direction
of arrow (A), causing the annulus gear to rotate faster (or more) than
in the case of 1 st
gear in proportion to the length that the long pinionhas “walked”.
The reduction ratio of
2nd gear is achieved in this way.
---

21-36AUTOMATIC TRANSAXLE - Transaxle Mechanism3RD GEAR
Forward
,sun gear
I, CarrierEndclutch
Front clutch
Reverse
Angear
17soo60
,When the shift is in
3rd gear in the “D” range, the rear clutch and the
front clutch are actuated. and other elements are all released.Therefore, driving force is transmitted from the forward sun gear and
the reverse sun gear.
Since the short and long pinions rotate in the same direction, they are
placed under a locked condition, causing the planetary gear set to
rotate as one unit.
lThis means that the engine rotation is directly connected, setting the
ratio between the input to and output from the planetary gear set to
1:1. The reduction ratio of 3rd gear is achieved in this way.Note that the end clutch is aotuated to provide for smooth shift
change to 4th gear.&