Mitsubishi Eclipse. Technical Information Manual (1994) - part 40

2-46

POWER TRAIN 

 Automatic Transaxle

Low/Reverse Clutch

Front planetary

carrier

Low-reverse

clutch

.

Transaxle case

Separator

Piston

Snap
ring

plates

retainer

spring

Reaction

plate

Clutch

Piston

discs

snap ring

The second clutch, located in the rear of the trans-
axle case, is the Low Reverse (L/R) clutch. The

 clutch is located in the very back of the case

and, as previously mentioned, shares the reaction
plate with the 2-4 clutch. Behind the reaction plate
is the clutch pack, belleville spring, 

 piston, and

piston retainer. The piston retainer is secured to
the case with three screws and sealed with a gasket.

The clutch is applied with line pressure from the
valve body that is directed through the transaxle
case to the piston retainer. This pushes the piston
forward and applies the clutch. When the clutch

is applied, it will lock or secure the front planetary

carrier to the transaxle case so it can not rotate.
When line pressure is released, the belleville spring

pushes the piston back to release the clutch.

POWER TRAIN 

 Automatic Transaxle

POWER TRAIN
Planetary Geartrain Assembly

Front sun

gear assembly

 thrust

 thrust

rear 
assembly

gear

front 
assembly

The entire planetary gear-train is located behind the

input clutch assembly and is inside the 2-4 and

 clutch assemblies. The planetary geartrain 

sists of two sun gears, two planetary carriers, two

 (ring) gears, and one output shaft.

2-4 clutch

Low-reverse

Splined to

Front Sun Gear Assembly

The front sun gear assembly rides in the center of the front
carrier and is welded to the center of two hubs that are arranged

back to back. Each of the hubs are splined to a clutch. The
front most hub is splined to the reverse clutch and when applied
turns the front sun gear. The rearward hub is splined to the
2-4 clutch and when applied prevents the front sun gear from
turning.

Front Carrier Assembly

The front planetary carrier and rear 

 (ring) gear are

splined together as one unit. When the overdrive clutch is
applied, it drives the front carrier assembly by the overdrive

hub. When the low/reverse clutch is applied, it holds or prevents

the front carrier assembly from rotating.

Rear Sun Gear

The rear sun gear is located in the center of the rear carrier

assembly. There are two thrust bearings located on either side
of the sun gear. When the underdrive clutch is applied, it drives
the rear sun gear through the underdrive hub and shaft.

2-48

POWER TRAIN 

 Automatic Transaxle

sha

Lugs for parking
pawl and output

speed sensor

gear

Rear Carrier Assembly

The rear planetary carrier, front 

 (ring) gear and output

shaft are all one assembly. The rear carrier assembly is respon-
sible for providing all output power for the transaxle assembly.
In other words, all output from the transaxle must go through
the rear carrier. The lugs around the outside of the assembly
have two purposes; to engage the parking pawl when the driver
selects “park”, and to generate an output speed signal used
by the TCM.
There are no clutches splined or connected to this unit in any

way. The rear carrier assembly is supported to the case by
two tapered roller bearings which must be set up with a specific
preload setting.

Planetary Geartrain Powerflow

The planetary gear-train in this transaxle provides
four forward gear ratios and one reverse gear ratio.
To obtain these different gear ratios, two planetary
carrier and pinion assemblies, two sun gears and
two 

 (ring) gears are used. Two shafts are

used as input to the planetary 

 the 

drive hub and shaft assembly, and the overdrive
hub with its shaft. The underdrive shaft protrudes

through, the center of the overdrive shaft and is
the longer of the two.
To achieve any output through the components of
this planetary 

 the following rules apply;

At least one component must be driven or turned,
one component must be held stationary (kept from

rotating), two components must be driven at the

same speed and in the same direction, and all output
from this 

 must go through the rear carrier

assembly.
The planetary gear-train is driven by three input
clutches. One of the input clutches must be applied
before the vehicle can move. A variety of gear ratios
are accomplished by using different input clutches
to turn different components of the planetary gear
set. Two clutches in the rear of the case must be
used to hold specific planetary components. When
going through the following power flows, keep in
mind that the gear-train must somehow complete
its power-flow by turning the rear carrier assembly.

If the output shaft/rear carrier assembly does not

turn, the vehicle will not move.

POWER TRAIN 

 Automatic Transaxle

2-49

First Gear

Underdrive clutch applied
(turns rear sun)

Low-reverse clutch applied
(holds rear 

 carrier)

In first gear range, torque input is through the under-

to “walk around” the inside of the stationary rear

drive clutch to the underdrive hub assembly. The

 gear. ‘The pinions are pinned to the rear 

underdrive hub is splined to the rear sun gear. When

carrier and cause the rear carrier assembly to rotate

the underdrive clutch is applied, it rotates the under-

as they “walk around” the 

 gear. This 

drive hub and rear sun gear. The 

 clutch is applied

vides the torque output for first gear. The other 

to hold the front carrier/rear 

 (ring gear)

tary 

 components are freewheeling. The first

assembly.

gear ratio is 

The rear sun gear drives the rear planetary pinion

gears. The rear planetary pinion gears are forced

Second Gear

Underdrive clutch applied
(turns rear sun)

2-4 clutch applied

(holds front sun)

Second gear is achieved by having both planetary

rear pinions rotate the rear 

 carrier 

gear sets contribute to torque multiplication. As in

sembly. The pinions of the front carrier will “walk

first gear, torque input is through the underdrive

around” the stationary front sun gear. This transmits

clutch to the rear sun gear. The 2-4 clutch is applied

torque to the front 

 carrier assembly

to hold the front sun gear stationary. The rotating

which provides output torque and a gear ratio of

rear sun gear turns the rear planetary pinions. The