1990 MITSUBISHI ECLIPSE differential

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3-8REAR AXLE - Viscous Coupling Type Limited Slip Differential
OPERATIONDrive force smaller
I(Slipping side)Drive force larger(Grippina side)
Rear drive shaft
(L.H.1 (Left wheel)
resistance smaller)Rear drive shaft
(R.H.1 (Right wheel)
11 PO071If a difference in rotating speed occurs between the
right and left wheels, the viscous coupling case @
and viscous coupling hub @ relatively rotate with
the same difference in rotating speed as the rear
drive shafts. As a result a differential limiting torque
is generated by the shear resistance of silicone oil
and helps suppress the differential (slipping).For example, assume that the right wheel rotates at
20 rpm due to the road surface resistance, whereas
the left wheel rotates at 30 rpm. The difference in
rotating speed between the right and left wheels is
10 rpm. Since the viscous coupling is provided
between the right and left wheels, a differential
limiting torque compensating for the difference of
10 rpm in rotating speed is transmitted from the left
wheel to the right one.
Therefore, a larger drive force is transmitted to the
right wheel rotating at the lower speed.

REAR AXLE- Differential Support Member3-9
DIFFERENTIAL SUPPORT MEMBER
ROJFAAAThe differential support member supports the rear
side of the differential carrier. That end of the
member which is mounted to the body is elastically
supported by use of rubber bushings.
Section A-ADifferential support
member
llA0297
cDifferential
support member
\Differential carrier

14-8
rFUEL SYSTEM
-Fuel Supply and Fuel Pressure Control
FUEL PUMP
This fuel pump is known as the in-tank type becauseit is located within the fuel tank itself, surrounded by
the fuel. For this reason, the pump operation noise
is well insulated, and it has excellent resistance to
vapor-locks.This type of pump is also called the “wet type”
because even its internal parts are in contact with
the fuel. With a construction that is the unification of
a ferrite-type DC motor and an impeller-type pump,
the pump itself is composed of the impeller, which
is driven by the motor, as well as the casing and the
cover. There are, in addition, a relief valve (a safety
valve for protection of the fuel-pressure circuit) and
a check valve (to maintain residual pressure).
The electric fuel pump has the following features:
l It has greater discharge pressure
mechanical-type fuel pump, as wellthan a
as lessdischarge pulsation.
lIt has a lower level of operation sound that the
electromagnetic type (Bendix type) of fuelpump.
PRESSURE-SUPPLY OF FUEL
When the impeller is caused to rotate by the motor,
a pressure differential develops at the upper. and
lower parts of the impeller, caused by the grooves in
the circumference of the impeller.
When this happens, a whirlpool effect is generated
within the fuel pump, causing the fuel pressure to
become higher, thereby causing the fuel to be
expelled from the pump chamber and to pass
through the motor, opening the check valve, and to
be discharged from the discharge port.
Discharge port
4Check!nRelief valve
DC mo
-lllll1 I/
Circum-ferential
flow pumr
II’ f-Pump
casing
J
Pumpcovert
lntakler 03R0071REWEF VALVE
If for some reason, such as an abnormal condition at the
_discharge side, the fuel were not to be discharged, the fuel
pressure within the fuel pump would become abnormally high.
Thus, when the pressure within the fuel pump reaches
450-600 kPa (64-85 psi), the relief valve opens and the
pressure escapes, so that, the fuel line pressure does not
increase to the regulated level or above.
CHECK VALVE
When the pump stops, the check valve is closed by spring
force, so that there is high pressure remaining within the fuel
line.By in this way maintaining a high pressure within the fuel line,
the restarting of the engine becomes easier, and vapor-locks at
high temperature are prevented.
-
-_..I
-~

-
REAR SUSPENSION -Double Wishbone Suspension17-13
Member supponbushingI
12AOO5
Upper arm
Link diagram of ordinarydouble wishbone suspension system
5. The suspension crossmember is mounted with the mem-
ber support bushing on the body. The input from the wheel
is first damped by the trailing arm and the bushings of the
lateral arms. It is then further damped by the member
support bushing. This dual anti-vibration construction
provides low vibration and low noise.
In addition, mounting of the differential carrier on this
crossmember decreases the natural frequency of the
crossmember, further damping vibrations.
The lower natural frequency of the crossmember allows
harder adjustment of the support bushing so that the
tendency toward oversteering of the suspension due to
side force, occurring during cornering can be reduced. This,
combined with understeering tendency by middle joint
.displacement described in (3) above, results in totally slight
understeering tendency.
Why this new rear suspension system is classified as a double
wishbone suspension
The new rear suspension is represented below by the diagram
as an aid to understanding its construction.
F-7-,12AOO33!A/ \
12AOO37Point A can rotate about rotary axis B-C and point
Dcan rotate about rotary axis E-C. The triangles ABC
and DEC can rotate like wishbone suspension
arms.When this is compared to an ordinary double
wishbone type suspension, it may be regarded asone with forward points
C, and C2 of the upper and
lower arms located at the same point. Thus, this
new rear suspension system is considered as a
double wishbone suspension system.

MANUAL TRANSAXLE <2WD> - General InformationF5M33
Clutch housing
Bearing retainer
\1st speedgear
2nd speed gear
I3rd speed gear
3rd-4th speed synchronizer assembly
4th speed gear
I5th speed gear
1 st-2nd
speedsynchro-
nizerassembly5th speed
synchronizer
assembly
- Rear Cover
. Reyerse gear
now-prevention
device
-5th speed inter
mediate gear
Intermediate
Differential drive gear
SpacerDrain plug
gear

MANUAL TRANSAXLE <4WD> - General Information
MANUAL TRANSAXLE <4WD>
GENERAL INFORMATION
W5M33 transaxle is a transaxle for 4WD, having
center differential mounted on the output shaft ofwheels. Using the viscous coupling as a device for
the conventional front
wheeledrive type transaxle solimiting differential of the center differential, this
as to distribute drive power to the front and reartransaxle is a full time 4WD type and provides
improved traction and easy drive.
SPECIFICATIONS
Item
Transaxle model
We
Gear ratio
1 St
2nd
3rd4th5th
Reverse
Primary reduction ratio
(number of gear teeth)
Front differential gear ratio
(number of teeth)Specifications
W5M33-2-NPZS
5-speed constant-mesh cable controlled type3.083
1.684
7.1150.833
0.666
3.166
1.275 (37/29).
3.866 (58/l
51
Transfer gear ratio(number of teeth)1.090 (24/22)
Speedometer gear ratio
Oil quantity
liter (qts.)
Transaxle
Transfer
Dry weight ic kg (Ibs.)
29 I36
2.3 (2.43)0.6
(0.63)
64.0(141)

--.-.--_ _ _-MANUAL TRANSAXLE
<4WD> - General Information
SECTIONAL VIEWN5M3321-7Clutch housing
1st speed gear
Input shaft
-Drive bevel gear
\r
l!
.IBearing retainer\
St-1
w
.
I,..\\I \ I I
2nd speed synchronizer assembly
2nd speed gear
3rd speed gear
3rd-4th speed synchronizer assembly
I4th speed gear
I5th speed gear
5th speed
intermediate gear
shaft
Center differential
Front differentialViscdus coupling
wMool4

_.c.
21-8MANUAL TRANSAXLE <4WD> - General Information4WD SYSTEM
Viscous couplingCenter differential
cous coupling
kCenth differential
I
IFro& differential
Rear differential
I
I
I [[lll,i, ‘- h-
1 p’f’ ,* , l/i\
/IViscous couplingL
(Option)
3
2210105CONSTRUCTION
OF THE 4WD SYSTEM
The 4WD system configuration and a section of the
center differential are shown above.The viscous coupling for the center differential is
The center differential is placed on the center shaftlocated on rear side of center differential.This
and engine power is transmitted to the front andarrangement makes the entire transaxle simpler a
rear drive shafts by means of a concentric dual shaftmore compact. Differential limiting by the
centc,construction.differential viscous coupling takes place between
the center differential case and the center shaft
(rear wheel drive shaft).