4t40e repair manual

4T40-EH

YD

RA

-MA

TIC CONTENTSINTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

HOW TO USE THIS BOOK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

UNDERSTANDING THE GRAPHICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

TRANSMISSION CUTAWAY VIEW (FOLDOUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

PRINCIPLES OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A

MAJOR MECHANICAL COMPONENTS (FOLDOUT) . . . . . . . . . . . . . . . . . . . 10

RANGE REFERENCE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

TORQUE CONVERTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

APPLY COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

PLANETARY GEAR SETS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

HYDRAULIC CONTROL COMPONENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

ELECTRONIC CONTROL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

POWER FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

COMPLETE HYDRAULIC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

LUBRICATION POINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

BUSHING, BEARING & WASHER LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 105

SEAL LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

ILLUSTRATED PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

BASIC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

PRODUCT DESIGNATION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

2

PREFACE

All information contained in this book is based on the latest data availableat the time of publication approval. The right is reserved to make productor publication changes, at any time, without notice.

No part of any GM Powertrain publication may be reproduced, storedin any retrieval system or transmitted in any form or by any means,including but not limited to electronic, mechanical, photocopying,recording or otherwise, without the prior written permission ofPowertrain Group of General Motors Corporation. This includes alltext, illustrations, tables and charts.

COPYRIGHT 1996 POWERTRAIN DIVISIONGeneral Motors Corporation

ALL RIGHTS RESERVED

The Hydra-matic 4T40-E Technicians Guide is intended for automotivetechnicians that are familiar with the operation of an automatic transaxle ortransmission. Technicians or other persons not having automatic transaxleor transmission know-how may find this publication somewhat technicallycomplex if additional instruction is not provided. Since the intent of thisbook is to explain the fundamental mechanical, hydraulic and electricaloperating principles, technical terms used herein are specific to thetransmission industry. However, words commonly associated with thespecific transaxle or transmission function have been defined in a Glossaryrather than within the text of this book.

The Hydra-matic 4T40-E Technicians Guide is intended to assist techniciansduring the service, diagnosis and repair of this transaxle. However, thisbook is not intended to be a substitute for other General Motors servicepublications that are normally used on the job. Since there is a wide rangeof repair procedures and technical specifications specific to certain vehiclesand transaxle models, the proper service publication must be referred towhen servicing the Hydra-matic 4T40-E transaxle.

1

The Hydra-matic 4T40-E Technicians Guide isanother Powertrain publication from the TechniciansGuide series of books. The purpose of thispublication, as is the case with other TechniciansGuides, is to provide complete information on thetheoretical operating characteristics of this transaxle.Operational theories of the mechanical, hydraulicand electrical components are presented in asequential and functional order to better explain theiroperation as part of the system.

In the first section of this book entitled Principlesof Operation, exacting explanations of the majorcomponents and their functions are presented. Inevery situation possible, text describes componentoperation during the apply and release cycle as wellas situations where it has no effect at all. Thedescriptive text is then supported by numerousgraphic illustrations to further emphasize theoperational theories presented.

The second major section entitled Power Flow,blends the information presented in the Principlesof Operation section into the complete transaxleassembly. The transfer of torque from the enginethrough the transaxle is graphically displayed on afull page while a narrative description is provided ona facing half page. The opposite side of the halfpage contains the narrative description of the

hydraulic fluid as it applies components or shiftsvalves in the system. Facing this partial page is ahydraulic schematic that shows the position of valves,checkballs, etc., as they function in a specific gearrange.

The third major section of this book displays theComplete Hydraulic Circuit for specific gearranges. Fold-out pages containing fluid flowschematics and two dimensional illustrations of majorcomponents graphically display hydraulic circuits.This information is extremely useful when tracingfluid circuits for learning or diagnosis purposes.

The Appendix section of this book providesadditional transaxle information regarding lubricationcircuits, seal locations, illustrated parts lists and more.Although this information is available in currentmodel year Service Manuals, its inclusion providesfor a quick reference guide that is useful to thetechnician.

Production of the Hydra-matic 4T40-E TechniciansGuide was made possible through the combinedefforts of many staff areas within the General MotorsPowertrain Division. As a result, the Hydra-matic4T40-E Technicians Guide was written to providethe user with the most current, concise and usableinformation available regarding this product.

3

INTRODUCTION

Principles of Operation section by showingspecific fluid circuits that enable the mechanicalcomponents to operate. The mechanical powerflow is graphically displayed on a full size pageand is followed by a half page of descriptive text.The opposite side of the half page contains thenarrative description of the hydraulic fluid as itapplies components or moves valves in the system.Facing this partial page is a hydraulic schematicwhich shows the position of valves, checkballs,etc., as they function in a specific gear range.Also, located at the bottom of each half page is areference to the Complete Hydraulic Circuitsection that follows.

The Complete Hydraulic Circuits section(beginning on page 81) details the entire hydraulicsystem. This is accomplished by using a fold-outcircuit schematic with a facing page twodimensional fold-out drawing of each component.The circuit schematics and component drawingsdisplay only the fluid passages for that specificoperating range.

Finally, the Appendix section contains a schematicof the lubrication flow through the transaxle,disassembled view parts lists and transaxlespecifications. This information has been includedto provide the user with convenient referenceinformation published in the appropriate vehicleService Manuals. Since component parts listsand specifications may change over time, thisinformation should be verified with ServiceManual information.

First time users of this book may find the page layouta little unusual or perhaps confusing. However, witha minimal amount of exposure to this format itsusefulness becomes more obvious. If you areunfamiliar with this publication, the followingguidelines are helpful in understanding the functionalintent for the various page layouts:

Read the following section, Understanding theGraphics to know how the graphic illustrationsare used, particularly as they relate to themechanical power flow and hydraulic controls(see Understanding the Graphics page 6).

Unfold the cutaway illustration of the Hydra-matic 4T40-E (page 8) and refer to it as youprogress through each major section. Thiscutaway provides a quick reference of componentlocation inside the transaxle assembly and theirrelationship to other components.

The Principles of Operation section (beginning onpage 9A) presents information regarding the majorapply components and hydraulic controlcomponents used in this transaxle. This sectiondescribes how specific components work andinterfaces with the sections that follow.

The Power Flow section (beginning on page 53)presents the mechanical and hydraulic functionscorresponding to specific gear ranges. Thissection builds on the information presented in the

4

HOW TO USE THIS BOOK

5Figure 1

HOW TO USE THIS BOOK

UNDERSTANDING THE GRAPHICS

The flow of transaxle fluid starts in the bottom panand is drawn through the filter, case assembly, channelplate assembly, spacer plate and gaskets, control valveassembly and into the oil pump assembly. This is abasic concept of fluid flow that is easily understoodby reviewing the illustrations provided in Figure 2.However, fluid may pass between the valve body,spacer plate, channel plate and other componentsmany times before reaching a valve or applying aclutch. For this reason, the graphics are designed toshow the exact location where fluid passes through acomponent and into other passages for specific gearrange operation.

To provide a better understanding of fluid flow in theHydra-matic 4T40-E transaxle, the components involvedwith hydraulic control and fluid flow are illustrated inthree major formats. Figure 3 (page 7-7A) provides anexample of these formats which are:

A three dimensional line drawing of thecomponent for easier part identification.

A two dimensional line drawing of the componentto indicate fluid passages and orifices.

6

A graphic schematic representation that displaysvalves, checkballs, orifices and so forth, requiredfor the proper function of the transaxle in a specificgear range. In the schematic drawings, fluidcircuits are represented by straight lines andorifices are represented by indentations in a circuit.All circuits are labeled and color coded to providereference points between the schematic drawingand the two dimensional line drawing of thecomponents.

Figure 4 (page 7B) provides an illustration oftypical valve, bushing and valve train components.A brief description of valve operation is alsoprovided to support the illustration.

Figure 5 (page 7B) provides a color coded chartthat references different fluid pressures used tooperate the hydraulic control systems. A briefdescription of how fluid pressures affect valveoperation is also provided.

Figure 2

BOTTOMPAN(24)

OILPUMP BODYASSEMBLY

(10)

CONTROLVALVE BODYASSEMBLY

(18)

CHANNELPLATE

ASSEMBLY(27)

SPACERPLATE

(23)

GASKETVALVE BODY/

SPACER PLATE(22)

GASKETSPACER PLATE/

CHANNEL PLATE(24)

1-2, 2-3 & 3-4ACCUMULATOR

ASSEMBLIES(29-32 &47)

INTERMEDIATE/4THSERVO

ASSEMBLY(68, 75-80) LO/REVERSE

SERVOASSEMBLY

(66-73)FILTER

ASSEMBLY(100)

CASEASSEMBLY

(51)

TORQUECONVERTER

(55)

#2

5

28b

29

28a

EX

LINE

PRESSURERELIEFVALVE

REVERSE INPUT CLUTCHASSEMBLY

(102)FORWARD CLUTCH

ASSEMBLY(110)

INTAKE & DECREASECONVERTER & LUBEMAINLINESOLENOID SIGNALACCUMULATORACTUATOR FEEDTORQUE SIGNAL

DRIVEN SPROCKETSUPPORT &

2ND CLUTCHASSEMBLY

(95)

DIRECT & COAST CLUTCHASSEMBLY

(105)

RELE

ASE

APPL

Y

TORQUECONVERTERASSEMBLY

(55)

GASKET (24)SPACER PLATE (23)

CONTROL VALVE BODY (300)

CASE (51)CHANNEL PLATE (27)

GASKET (22)

1-2/3-4 ACCUMULATOR 1-2/3-4 ACC

EX

EX

32 18

#4

24

1-2 ACCUM FD

3-4ACCUMULATOR

4TH

BAND

3-4

ACCU

MUL

ATOR

FEE

D

#7

28

3-4 ACCUM FD

21

EX

23

19

31

LO

PRN

LO/P

RN

#1

PRN/

EX

PRND4D3D2D1

LO D21

D321

DRIV

E

LINE

PRND

4

PRND

4

PRN

PRN

PRN

PRN

REVE

RSE

MANUAL VALVE

#6

25

DIRECT CL

DIRECT CLUTCH FEED

#5

26

2-3 ACC FD

27

2-3 DRIVE LO & REVERSESERVO

REVERSE

REVE

RSE

REVE

RSE

LO BAND

LO B

AND

LOPRND4

REV

D21

REL

DRIVE

TEMPERATURESENSOR

PRESSURESWITCH

MANIFOLD

LO

DRIVE

DRIV

E

LINE

PRND4

REVERSE

RELEASE

D21

SUCT

ION

SUCT

ION

OIL LEVEL CONTROL

LINE

DECREASE

OILPUMP

DECREASEBLEED

COOLER

COOL

ER

LUBE

1

GASKET (24)SPACER PLATE (23)

CONTROL VALVE BODY (300)

CASE (51)

CHANNEL PLATE (27)

CHANNEL PLATE (27)

GASKET (22)

OIL LEVELCONTROL VALVE

(86)

FILT

ERED

ACT

UATO

R FD

3DE

CREA

SE

1

FILTERASSEMBLY

(85)

BOTTOMPAN(88)

LINE

LINE

LINEPRESSURE

TAP(48)

2d7 2g

LINE

2e

2f 20a

20b

18c

18d

18e

2c 2b4a4b

5a13a

13b 5

c

225b

5d 45c

46

24b

23d

24a

24c

25a

23c6b 6

c 6a

8

CHAINLUBE

10a 1

0b 20e

20f

2a

22c

21c

44d

16 15b

17b

15c 17a

11b12

12a

11a

14a 1

4b 36b

35d

36a

35c

18b

14c

18a

15a

17c

10

21b

20d20c

21a

22b

20h20g

22a

2023a 2

3b

25b26a

26b

26c

26d

OILFEED TUBEASSEMBLY

(83)

27b

27a

27c

FORWARD CLUTCH

LUBE

2 (T

o Fo

rwar

d Cl

utch

Sup

port

Asse

mbl

y)

36e

37b

36d

36c

37a

2-3ACCUMULATOR

DIRE

CT C

L FD

2-3

ACCU

MUL

ATOR

FEE

D

45d

EX

45b

45a

45e

30a

30b

30c

30d

30e3

2b30

g

3130

h

32a

30f

32c

1-2ACCUMULATOR

1-2

ACCU

M F

D

32d

38a

38b

39b

39a

39c

1239d

40

41

44b

44a

44c

8

INTERMEDIATE BAND

INT

BAND

INTE

RMED

IATE

BAN

D

DIRE

CT C

LUTC

H

43e

43d

INTERMEDIATE4TH

SERVO

4TH BANDINTERMEDIATE BAND

43f

#3

43c

43b

43a

EXEX

D21D21D21EX

ACTUATORFILTER

FILTERED ACT FD

ACT FD

TORQUE SIG REG

PRESSURECONTROLSOLENOID

EX

TORQUE SIGNAL

TORQUE SIG

LINEFILT ACT FD

VBS SIGNAL

EX EX

ACT FD LIMIT VALVE

EX EX EX

LINEACT FEED

14

ORIFICED EX

45f

46

3-4 SHIFT VALVE

INT

BD F

D

D321

D321

D321

D321

D321

D321

1-2 SIGNAL

ACTUATOR FDACT FD

3-4 DRIVE

4TH

BD EX

2-3 SHIFT VALVE2-3 SHIFTSOLENOIDN.O. OFF

D21

EX

2-3 SIGNAL

2-3 DRIVE3-4 DRIVE

EXEX

ACTUATOR FEEDINT BD FD

COAST CL

COAS

T CL

UTCH

EX

1-2 SIGNAL

1-2 SHIFT VALVE1-2 SHIFTSOLENOIDN.O. ON

2-3

SIGN

AL

2-3 SIGNAL

2-3

DRIV

E

LO/P

RNLO

BAN

DEX EXE

X

INT

BAND

REVERSEDRIVE

ACTUATOR FEED

14d

42b17

TCC CONTROL

EX

RELEASEEX

COOLER

APPLY

TCC FEED LIMIT

33a

34a

33b3

4bTCC FEED LIMIT VALVE

EX EX

CONV FEEDTCC FEED LIMIT

TCC FD LIMIT

TCC FEED LIMIT

EX

2-3 ACCUM VALVE

EXEX

TORQUE SIGLINE

2-3 ACCUM2-3 ACCUMULATOR

LINE

1-2/

3-4

ACC

EXEXT S

IG

1-2/3-4 ACCUMULATOR

1-2/

3-4

ACC

TCCCONTROLPWMSOLENOID

TCC REG APPLY VALVE

EX

EXEX

T SI

G (P

WM

)

TCC

SIGN

AL (P

WM

)

LINE

TCC

R AP

P

TCC

REG

APPL

YTC

C RE

G AP

PLY

FILTERED 2-3 DR

REVERSE

LUBE

2

CONV

FD

EX EX

DECREASE

BOOST VALVE PRESS REG

LINE

LINE

LINE

TORQ

UE S

IG

42a

DIRECT CL

COAST CL

LUBE 1

2ND CL

REVE

RSE

CLUT

CH

DIRE

CT C

LUTC

H

COAS

T CL

UTCH

FORW

ARD

CLUT

CHFO

RWAR

D CL

UTCH

ORIFICED EX

REVERSE CLUTCH

FILTER (17)

30

3 4 10c 13

35b 3

5a

2-3

ACC

FD

1

7

2

DRIVE DRIVE

DRIV

E

DRIV

E

FORWARD CLUTCHFORWARD CLUTCH

TORQUE SIGNAL

LUBE 2

LUBE 2

LUBE

2

3-4 ACCUM FD

4TH BAND

4TH

BAND

REV

REV

4TH BAND 4TH BAND

TORQ

UE S

IG

TORQ

UE S

IG

LO

LOLOLO

2ND CL

2ND CLUTCH

LINE

LINE

LINELINE

LINE

LINE

LINE

LINE

CONV

ERTE

R FE

ED

TCC

FD L

IMIT

TCC

FD L

IMIT

RELE

ASE

RELEASE

RELE

ASE

RELE

ASE

APPL

Y

APPL

Y

APPL

Y

2ND

CLUT

CH

LUBE 1

LUBE

1

COOL

ER

COOL

ER

LUBE

2

11

LO/PRN

PRND4

PRND4

PRND4PRND4

PRND4PRND4

PRND

4

LO B

AND

LO BAND

ACT

FD

ACT FD

ACTUATOR FEED

ACT

FD

1-2

SIG

2-3

SIGN

AL

2-3 SIG

TORQ

UE S

IGNA

LTO

RQUE

SIG

NAL

TORQUE SIGNAL

2-3

ACCU

M

2-3

ACCU

M

2-3 ACCUMULATOR FEED 2-3 ACCUMULATOR FEED

REVE

RSE

CLUT

CH

REVERSE CLUTCH

REVERSEREVERSE

REVERSE

REVE

RSE

DRIVE DRIVE

2-3 DR

2-3

DRIV

E

2-3

DR

2ND

CLUT

CH2N

D CL

UTCH

2ND CL

3-4

DRIV

E

D C F

DIRE

CT C

L FD

DIRE

CT C

LUTC

H

DIRECT CLUTCHINTERMEDIATE BAND

COAS

T CL

UTCH

INTE

RMED

IATE

BAN

D FD

EX

EX



DR

IVEN

SPR

OCK

ET

SUPP

ORT

(95)

CHAN

NEL

PLAT

E (27

)

6

29

16

UNDERSTANDING THE GRAPHICS

Figure 3

PUMP COVER SIDE CHANNEL PLATE SIDE VALVE BODY SIDE

CHANNEL PLATE SIDE

THREE DIMENSIONALTHREE DIMENSIONALTHREE DIMENSIONAL

TWO DIMENSIONAL TWO DIMENSIONAL TWO DIMENSIONAL TWO DIMENSIONAL

THREE DIMENSIONAL

GRAPHICSCHEMATIC

REPRESENTATIONCHANNEL PLATE FACE

TWO DIMENSIONALTHREE DIMENSIONAL

TWO DIMENSIONALTHREE DIMENSIONAL

CONTROL VALVE BODY SIDE

CONTROLVALVE BODY

ASSEMBLY (18)

OILPUMP BODY

(10)

CHANNEL PLATEASSEMBLY (27)

DRIVENSPROCKETSUPPORT

ASSEMBLY(95)

CASEASSEMBLY

(51)

VALVE BODYSPACERPLATE

(23)

FOLDOUT 7AFOLDOUT 7

GASKET(22)

GASKET(24)

SPACERPLATE

(23)

DRIVEN SPROCKETSUPPORT

ASSEMBLY(95)

CASEASSEMBLY

(51)

7B

FLUID PRESSURES

INTAKE & DECREASE

CONVERTER & LUBE

MAINLINE

SOLENOID SIGNAL

ACCUMULATOR

ACUATOR FEED

TORQUE SIGNAL

EXHAUST

DIRECTION OF FLOW

A B

A B

WITH EQUAL SURFACE AREASON EACH END OF THE VALVE,BUT FLUID PRESSURE "A"BEING GREATER THAN FLUIDPRESSURE "B", THE VALVEWILL MOVE TO THE RIGHT.

WITH THE SAME FLUID PRESSUREACTING ON BOTH SURFACE "A"AND SURFACE "B" THE VALVEWILL MOVE TO THE LEFT. THISIS DUE TO THE LARGER SURFACEAREA OF "A" THAN "B".

UNDERSTANDING THE GRAPHICSTYPICAL BUSHING & VALVE

Figure 4

Figure 5

SPRING

RETAININGPIN

BOREPLUG

VALVE

BUSHING

EXHAUST FROM THEAPPLY COMPONENTUNSEATS THE CHECKBALL,THEREFORE CREATINGA QUICK RELEASE.

TO APPLYCOMPONENT APPLY FLUID SEATS THE

CHECKBALL FORCING FLUIDTHROUGH AN ORIFICE INTHE SPACER PLATE, WHICHCREATES A SLOWER APPLY.

WITH SIGNAL FLUID PRESSUREGREATER THAN SPRING ANDSPRING ASSIST FLUID PRESSURETHE VALVE MOVES OVER.

WITH SIGNAL FLUID PRESSUREEQUAL TO OR LESS THANSPRING AND SPRING ASSISTFLUID PRESSURE THE VALVEREMAINS IN CLOSED POSITION.

BUSHING

VALVEBODY

SPACERPLATE

RESTRICTINGORIFICE

CHECKBALL

RETAININGPIN

BOREPLUG

SPRINGVALVE

BUSHING

VALVEBODY

SPACERPLATE

SIGNALFLUID

APPLYFLUID

SPRINGASSISTFLUID

EX

SPACERPLATE

SIGNALFLUID

APPLYFLUID

SPRINGASSISTFLUID

EX

NOTE: NOT ALL VALVES ARE USED WITH A BUSHING

HYDRA-MATIC 4T40-E

8 Figure 6

2NDCLUTCH

DRIVENSPROCKET

MANUALSHAFT

TORQUECONVERTER

DRIVELINK

ASSEMBLY

OUTPUTSPEED

SENSOR

DRIVESPROCKET

REVERSECLUTCH

DIRECTCLUTCH

FORWARDCLUTCH

COASTCLUTCH

LOROLLERCLUTCH

OILPUMP

ASSEMBLY

CONTROLVALVE BODYASSEMBLY

INPUTSPEED

SENSOR

OUTPUTSHAFT

2NDROLLERCLUTCH

INTERMEDIATE/4THBAND

FILTERASSEMBLY

INPUTSPRAG CLUTCH

ASSEMBLY

LO/REVERSEBAND

FORWARDCLUTCH

SUPPORT

DIFFERENTIALASSEMBLY

OUTPUTSTUBSHAFT

FINALDRIVE

ASSEMBLY

LO/REVERSESERVO

INPUTPLANETARYGEAR SET

REACTIONPLANETARYGEAR SET

HYDRA-MATIC 4T40-ECROSS SECTIONAL DRAWING

A cross sectional line drawing is typically the standardmethod for illustrating either an individual mechanicalcomponent or a complete transaxle assembly. However,unless a person is familiar with all the individualcomponents of the transaxle, distinguishing componentsmay be difficult in this type of drawing. For thisreason, a three dimensional perspective illustration(shown on page 8) is the primary drawing usedthroughout this book.

The purpose for this type of illustration is to provide amore exacting graphic representation of each componentand to show their relationship to other componentswithin the transaxle assembly. It is also useful for

understanding the cross sectional line drawing bycomparing the same components from the threedimensional perspective illustration. In this regard itbecomes an excellent teaching instrument.

Additionally, all the illustrations contained in this bookuse a color scheme that is consistent throughout thisbook. In other words, regardless of the type ofillustration or drawing, all components have an assignedcolor and that color is used whenever that componentis illustrated. This consistency not only helps to providefor easy component identification but it also enhancesthe graphic and color continuity between sections.

8A

Figure 7

GENERAL DESCRIPTION

The transaxle can be operated in any one of the sevendifferent positions shown on the shift quadrant(Figure 8).P Park position enables the engine to be started whilepreventing the vehicle from rolling either forward orbackward. For safety reasons, the vehicles parkingbrake should be used in addition to the transaxle Parkposition. Since the final drive differential and outputshaft are mechanically locked to the case through theparking pawl and final drive internal gear, Park positionshould not be selected until the vehicle has come to acomplete stop.R Reverse enables the vehicle to be operated in arearward direction.N Neutral position enables the engine to start andoperate without driving the vehicle. If necessary, thisposition should be selected to restart the engine whilethe vehicle is moving.D Overdrive range should be used for all normal

driving conditions for maximum efficiency and fueleconomy. Overdrive range allows the transaxle to operatein each of the four forward gear ratios. When operatingin the Overdrive range, shifting to a lower or higher gearratio is accomplished by depressing the accelerator.

It is not recommended that the transaxle be operated inOverdrive range when pulling heavy loads or drivingon extremely hilly terrain. Typically these conditionsput an extra load on the engine, therefore the transaxleshould be driven in a lower manual range selection formaximum efficiency.3 Manual Third should be used when drivingconditions dictate that it is desirable to use only threegear ratios. These conditions include towing a trailer ordriving on hilly terrain as described above. This rangeis also helpful for engine braking when descendingslight grades. If the vehicle is in fourth gear it willimmediately shift to third when Manual Third isselected. Automatic shifting is the same as in Overdriverange for first, second and third gears except thetransaxle will not shift into fourth gear.2 Manual Second should be used when drivingconditions dictate that it is more desirable to use onlytwo gear ratios. It has the same starting ratio (firstgear) as Manual Third but the transaxle is preventedfrom shifting above second gear at normal throttleopening. If the transaxle is in third or fourth gear,when Manual Second is selected, it will shift to secondgear below approximately 100 kmh (62 mph). ManualSecond can be selected for engine braking as required.1 Manual First can be selected at any vehicle speed.If the transaxle is in second, third or fourth gear it willshift into first gear below approximately 60 kmh (37mph). This is particularly beneficial for maintainingmaximum engine braking when descending steep grades.

Figure 8

EXPLANATION OF RANGES

The PCM commands shift solenoids, within thetransaxle, on and off to control shift timing. The PCMalso controls the apply and release of the torqueconverter clutch which allows the engine to deliver themaximum fuel efficiency without sacrificing vehicleperformance.The hydraulic system primarily consists of a vane typepump, control valve body and channel plate. The pumpmaintains the working pressures needed to stroke theservos and clutch pistons that apply or release thefriction components. These friction components (whenapplied or released) support the automatic shiftingqualities of the transaxle.The friction components used in this transaxle consistof five multiple disc clutches and two bands. Themultiple disc clutches combine with three mechanicalcomponents, two roller clutches and a sprag clutch, todeliver five different gear ratios through gear sets. Thegear sets then transfer torque through the final drivedifferential and out to the drive axles.

The Hydra-matic 4T40-E is a fully automatic, fourspeed, front wheel drive transaxle. It consists primarilyof a four-element torque converter, two planetary gearsets, a hydraulic pressurization and control system,friction and mechanical clutches and, a final driveplanetary gear set with a differential assembly.The four-element torque converter contains a pump, aturbine, a pressure plate splined to the turbine, and astator assembly. The torque converter acts as a fluidcoupling to smoothly transmit power from the engineto the transaxle. It also hydraulically provides additionaltorque multiplication when required. The pressure plate,when applied, provides a mechanical direct drivecoupling of the engine to the transaxle.The two planetary gear sets provide the four forwardgear ratios and reverse. Changing gear ratios is fullyautomatic and is accomplished through the use of aPowertrain Control Module (PCM). The PCM receivesand monitors various electronic sensor inputs anduses this information to shift the transaxle at theoptimum time.

FOLDOUT 9

PR

N D 3 21

PRINCIPLES OF OPERATION

An automatic transaxle is the mechanicalcomponent of a vehicle that transfers power(torque) from the engine to the wheels. Itaccomplishes this task by providing a numberof forward gear ratios that automaticallychange as the speed of the vehicle increases.The reason for changing forward gear ratiosis to provide the performance and economyexpected from vehicles manufactured today.On the performance end, a gear ratio thatdevelops a lot of torque (through torquemultiplication) is required in order to initiallystart a vehicle moving. Once the vehicle is inmotion, less torque is required in order tomaintain the vehicle at a certain speed. Oncethe vehicle has reached a desired speed,economy becomes the important factor andthe transaxle will shift into overdrive. At thispoint output speed is greater than input speed,and, input torque is greater than output torque.

Another important function of the automatictransaxle is to allow the engine to be started

and run without transferring torque to thewheels. This situation occurs whenever Park(P) or Neutral (N) range has been selected.Also, operating the vehicle in a rearwarddirection is possible whenever Reverse (R)range has been selected (accomplished by thegear sets).The variety of ranges in an automatic transaxleare made possible through the interaction ofnumerous mechanically, hydraulically andelectronically controlled components inside thetransaxle. At the appropriate time and sequence,these components are either applied or releasedand operate the gear sets at a gear ratio consistentwith the drivers needs. The following pagesdescribe the theoretical operation of themechanical, hydraulic and electrical componentsfound in the Hydra-matic 4T40-E transaxle.When an understanding of these operatingprinciples has been attained, diagnosis of thesetransaxle systems is made easier.

9A

OUTPUTSHAFT

(94)

FINAL DRIVESUN GEAR

SHAFT(651)

SPLINEDTOGETHER

MAJOR MECHANICAL COMPONENTS

10 Figure 9

PARK LOCKGEAR(659)

FINAL DRIVESUN GEAR

(115)

DIFFERENTIAL& FINAL DRIVE

ASSEMBLY(116)

SPLINEDTOGETHER

PARKING LOCKPAWL(663)

PARKING LOCKACTUATOR ASSEMBLY

(807)

FORWARD CLUTCHSUPPORT

(656)

FINAL DRIVEINTERNAL GEAR

(118)

OIL PUMPDRIVE SHAFT

(19)

DRIVE LINKASSEMBLY

(36)

DRIVESPROCKET

(37) TURBINESHAFT

(39)

SPLINED TOTORQUE CONVERTERTURBINE ASSEMBLY

(D)

SPLINED TOOIL PUMP

ROTOR(204)

SPLINED TOCONVERTER HOUSING

COVER ASSEMBLY(J)

SPLINEDTO

(105)

SPLINEDTO

(526)

SPLINEDTO

(511)

SPLINEDTO

(659 & 115)

DRIVENSPROCKET

(91)

TRANSAXLECASE(51)

INTERMEDIATE/4TH BAND

(100)

REVERSE INPUTCLUTCH ASSEMBLY

(102)

DIRECT & COASTCLUTCH ASSEMBLY

(105)

REACTIONSUN GEAR& SHELL

(529)

DRIVEN SPROCKETSUPPORT ASSEMBLY

(95)

2ND CLUTCHPLATE

ASSEMBLY (96-99)

2ND ROLLERCLUTCH

ASSEMBLY (452)

INTERMEDIATE/4THSERVO ASSEMBLY

(68, 70, 75-80)

LO/REVERSESERVO ASSEMBLY

(66-73)

FORWARDCLUTCH ASSEMBLY

(110)

LO/REVERSEBAND(111)

INPUT FLANGE &FORWARD CLUTCH HUB

ASSEMBLY (108)

INPUTCARRIER ASSEMBLY

(106)

REACTIONCARRIER ASSEMBLY

(531)

INPUTSUN GEAR

(533)

SPLINEDTO(91)

TANGEDTO

(102)

TANGEDTO

(529)

LO ROLLERCLUTCH

ASSEMBLY(652)

SPLINED TO(651)

SPLINED TOTRANSAXLE CASE

(51)

SPLINED TOTRANSAXLE CASE

(51)

TANGEDTO

(110)

TANGEDTO

(531)

SPLINEDTO

(531)

SPLINEDTO

(533)

OUTPUTSTUB SHAFT

(58)

COLOR LEGENDMAJOR MECHANICAL COMPONENTSThe foldout graphic on page 10 contains a disassembled drawingof the major components used in the Hydra-matic 4T40-Etransaxle. This drawing, along with the cross sectionalillustrations on pages 8 and 8A, shows the major mechanicalcomponents and their relationship to each other as a completeassembly. Therefore, color has been used throughout this bookto help identify parts that are splined together, rotating at enginespeed, held stationary, and so forth. Color differentiation isparticularly helpful when using the Power Flow section forunderstanding the transaxle operation.

The color legend below provides the general guidelinesthat were followed in assigning specific colors to the majorcomponents. However, due to the complexity of thistransaxle, some colors (such as grey) were used for artisticpurposes rather than being restricted to the specific functionor location of that component.

Components held stationary in the case or splined tothe case. Examples: Driven Sprocket Support (95),Control Valve Body Asssembly (18).Components that rotate at engine speed. Examples:Torque Converter Assembly (55) and Oil Pump DriveShaft (19), Input Flange & Forward Clutch HubAssembly (108).Components that rotate at turbine speed. Examples:Converter Turbine, Drive Sprocket (37), DrivenSprocket (91) and Direct & Coast Clutch and InputShaft Housing Assembly (502).Components that rotate at transaxle output speed.Examples: Differential Carrier (116), Output Shaft(94).Components such as the 2nd Clutch Fiber Plates(98), 2nd Roller Clutch Cam (451).Components such as the Stator in the TorqueConverter (55).Components such as the Reverse Clutch Housing(454) and the Reaction Carrier Shaft Shell (526).Components such as the Input Sun Gear Shaft andInner Race Assembly (511), Input Sun Gear (533).Components such as the Input Carrier (106),Forward Clutch Assembly (110).Components such as the Reaction Carrier (531),Final Drive Sun Gear (115).

Accumulators, Servos and Bands.

All bearings and bushings.

All seals

10A

COLOR LEGEND

10B

APPLY COMPONENTSThe Range Reference Chart on page 11, provides anothervaluable source of information for explaining the overall functionof the Hydra-matic 4T40-E transaxle. This chart highlights themajor apply components that function in a selected gear range,and the specific gear operation within that gear range.

Included as part of this chart is the same color reference to eachmajor component that was previously discussed. If a componentis active in a specific gear range, a word describing its activitywill be listed in the column below that component. The rowwhere the activity occurs corresponds to the appropriate transaxlerange and gear operation.

An abbreviated version of this chart can also be found at the topof the half pages of text located in the Power Flow section andat the bottom of the half pages of text located in the CompleteHydraulic Circuits section. This provides for a quick referencewhen reviewing the mechanical power flow informationcontained in those sections.

RANGE REFERENCE CHART

Figure 10 11

4T40-E GEAR RATIOSFIRST 2.960SECOND 1.626THIRD 1.000FOURTH 0.681REVERSE 2.143

SHIFT SHIFT 2ND LORANGE GEAR A B 2ND ROLLER INT/4TH REVERSE COAST INPUT DIRECT FORWARD LO/REV. ROLLER

SOL SOL CLUTCH CLUTCH BAND CLUTCH CLUTCH SPRAG CLUTCH CLUTCH BAND CLUTCH

PARK N ON OFF HOLDING* APPLIED

REV R ON OFF APPLIED APPLIED

NEU N ON OFF HOLDING* APPLIED

1st ON OFF HOLDING APPLIED HOLDING

OVER-

D2nd OFF OFF APPLIED HOLDING HOLDING APPLIED RUNNING

OVER- OVER-3rd OFF ON APPLIED* RUNNING HOLDING APPLIED APPLIED RUNNINGOVER- OVER-

4th ON ON APPLIED* APPLIED RUNNING APPLIED APPLIED* RUNNING

1st ON OFF APPLIED HOLDING APPLIED HOLDING

OVER-3 2nd OFF OFF APPLIED HOLDING APPLIED HOLDING APPLIED RUNNINGOVER- OVER-3rd OFF ON APPLIED* RUNNING APPLIED HOLDING APPLIED APPLIED RUNNING

1st ON OFF APPLIED HOLDING APPLIED HOLDING

OVER-2 2nd OFF OFF APPLIED HOLDING APPLIED APPLIED HOLDING APPLIED RUNNINGOVER- OVER-3rd** OFF ON APPLIED* RUNNING APPLIED HOLDING APPLIED APPLIED RUNNING

1st ON OFF APPLIED HOLDING APPLIED APPLIED HOLDING

OVER-1 2nd*** OFF OFF APPLIED HOLDING APPLIED APPLIED HOLDING APPLIED RUNNINGOVER- OVER-3rd** OFF ON APPLIED* RUNNING APPLIED HOLDING APPLIED APPLIED RUNNING

ON = SOLENOID ENERGIZEDOFF = SOLENOID DE-ENERGIZED

* = APPLIED WITH NO LOAD.** = MANUAL FIRST AND SECOND THIRD GEAR IS ONLY AVAILABLE ABOVE APPROXIMATELY 100 km/h (62 mph).

*** = MANUAL FIRST SECOND GEAR IS ONLY AVAILABLE ABOVE APPROXIMATELY 60 km/h (37 mph).NOTE: MANUAL FIRST THIRD GEAR IS ALSO POSSIBLE AT HIGH VEHICLE SPEED AS A SAFETY FEATURE.

TORQUE CONVERTER

Figure 1112

CONVERTER HOUSINGCOVER ASSEMBLY

(J)

PRESSURE PLATEASSEMBLY

(G)

DAMPERASSEMBLY

(F)

TURBINETHRUSTSPACER

(H)

PRESSUREPLATE

SPRING(E)

TURBINEASSEMBLY

(D)

STATORASSEMBLY

(C)

CONVERTER PUMPASSEMBLY

(A)

THRUSTBEARING

ASSEMBLY(B)

THRUSTBEARING

ASSEMBLY(B)

A

H

G

D

E

F

B

C


(55)

TURBINESHAFT

(39)

DRIVESPROCKETSUPPORT

(43)

J

OIL PUMPDRIVE SHAFT

(19)

To reduce torsional shock during the apply of the pressure plateto the converter cover, a spring loaded damper assembly (F) isused. The pressure plate is attached to the pivoting mechanismof the damper assembly which allows the pressure plate torotate independently of the damper assembly up to approxi-mately 45 degrees. During engagement, the springs in the damperassembly cushion the pressure plate engagement and also re-duce irregular torque pulses from the engine or road surface.

PRESSURE PLATE, DAMPER AND CONVERTER HOUSINGCOVER ASSEMBLIESThe pressure plate is splined to the turbine hub and applies(engages) with the converter cover to provide a mechanicalcoupling of the engine to the transaxle. When the pressure plateassembly is applied, the small amount of slippage that occursthrough a fluid coupling is eliminated, thereby providing a moreefficient transfer of engine torque to the drive wheels.

TORQUE CONVERTERThe torque converter (55) is the primary componentfor transmittal of power between the engine and thetransaxle. It is bolted to the engine flywheel so that itwill rotate at engine speed. Some of the major functionsof the torque converter are: to provide for a smooth conversion of torque from the

engine to the mechanical components of the transaxle to multiply torque from the engine enabling the vehicle

to achieve additional performance when required to mechanically operate the transaxle oil pump through

the pump drive shaft (19) to provide a mechanical link, or direct drive,

from the engine to the transaxle throughthe use of a Torque ConverterClutch (TCC)

The torque converterassembly is made upof the following fivemain subassemblies: a converter pump assembly

(A) which is the driving member a turbine assembly (D) which

is the driven or output member a stator assembly (C) which is the

reaction member located between thepump (A) and turbine (D) assemblies

a pressure plate assembly (G) splinedto the turbine assembly (D) to enable directmechanical drive

a converter housing cover assembly (J) which is weldedto the converter pump assembly (A)

CONVERTER PUMP ASSEMBLY AND TURBINEASSEMBLYWhen the engine is running, the converter pumpassembly acts as a centrifugal pump by picking upfluid at it's center and discharging it at it's rim, betweenthe blades. The force of this fluid then hits the turbineblades and causes the turbine to rotate. As the engineand converter pump increase RPM, so does the turbine.

Torque converterfailure could causeloss of drive andor loss of power.

Figure 12

Figure 13

TORQUE CONVERTER

13

STATOR

CONVERTER ATCOUPLING SPEED

FLUID FLOWFROM TURBINE

CONVERTERMULTIPLYING

STATOR HELDFLUID FLOW REDIRECTED

STATOR ROTATESFREELY

FLUID FLOW

TURBINEASSEMBLY

(D)

CONVERTER PUMPASSEMBLY

(A)

STATORASSEMBLY

(C)

Stator roller clutch failure roller clutch freewheels in both directions can

cause poor acceleration at low speed. roller clutch locks up in both directions can

cause poor acceleration at high speed.

STATOR ASSEMBLYThe stator assembly is located between thepump assembly and turbine assembly, and ismounted on a one-way roller clutch. Thisone-way roller clutch allows the stator torotate in one direction and prevents (holds)the stator from rotating in the other direction.The function of the stator is to redirect fluidreturning from the turbine in order to assistthe engine in turning the converter pumpassembly.At low vehicle speeds when greater torqueis needed, fluid from the turbine hits thefront side of the stator blades (the converteris multiplying torque). At this time, the one-way roller clutch prevents the stator fromrotating in the same direction as the fluidflow, thereby redirecting fluid to assist theengine in turning the converter pump. Inthis mode, fluid leaving the converter pumphas more force to turn the turbine assemblyand multiply engine torque.As vehicle speed increases and less torque isrequired, centrifugal force acting on the fluidchanges the direction of the fluid leaving theturbine such that it hits the back side of thestator blades (converter at coupling speed).When this occurs, the roller clutch overrunsand allows the stator to rotate freely. Fluidis no longer being redirected to the converterpump and engine torque is not beingmultiplied.

Overheated fluid.

TORQUE CONVERTER

Figure 1414

TCC APPLIED

RELEASEFLUID

APPLYFLUID

APPLYFLUID


(55)

TURBINESHAFT

(39)


(43)

OIL PUMPDRIVE SHAFT

(19)

TCC RELEASED

RELEASEFLUID

APPLYFLUID

RELEASEFLUID


(55)

TURBINESHAFT

(39)


(43)

OIL PUMPDRIVE SHAFT

(19)

APPLYWhen the PCM determines that the vehicle is at theproper speed for the torque converter clutch to apply itsends a signal to the TCC PWM solenoid. The TCCPWM solenoid then routes line fluid from the pump tothe apply passage of the torque converter. The applypassage is a hole between two seals on the turbineshaft. The fluid flows inside the turbine shaft within anoil sleeve, then out of the sleeve and into the converterhub/drive sprocket support. Fluid passes through a holein the support and into the torque converter on theapply side of the pressure plate assembly.Apply fluid pressure forces the pressure plate againstthe torque converter cover to provide a mechanicallink between the engine and the turbine. Releasefluid is then routed out of the torque converterbetween the turbine shaft and the pump shaft.The TCC apply should occur in fourth gear (alsothird gear in some applications), and should not applyuntil the transaxle fluid has reached a minimumoperating temperature of 8C (46F) and the enginecoolant temperature reaches 50C (122F).For more information on TCC apply and release, seeOverdrive Range Fourth Gear TCC Released andApplied, pages 70-71.

RELEASEWhen the torque converter clutch is released, fluid isfed into the torque converter by the pump into therelease fluid passage. The release fluid passage islocated between the oil pump drive shaft (19) and theturbine shaft (39). Fluid travels between the shafts andenters the release side of the pressure plate at the endof the turbine shaft. The pressure plate is forced awayfrom the converter cover and allows the torque converterturbine to rotate at speeds other than engine speed.

The release fluid then flows between the frictionelement on the pressure plate and the converter coverto enter the apply side of the torque converter. Thefluid then exits the torque converter through the applypassage which goes into the drive sprocket supportand on through an oil sleeve within the turbine shaft.This fluid now travels to the valve body and on tothe oil cooler.

Once the TCC is applied there is no torque converter fluidcoupling assistance. Engine or driveline vibration could beunnoticeable before TCC engagement.

The primary function of any apply component is to holdor cause to drive, a member of a planetary gear set.

The Apply Components section is designed toexplain the function of the hydraulic and mechanicalholding devices used in the Hydra-matic 4T40-Etransaxle. Some of these apply components, such asclutches and bands, are hydraulically applied andreleased in order to provide automatic gear rangeshifting. Other components, such as a roller clutchor sprag clutch, often react to a hydraulically appliedcomponent by mechanically holding or releasinganother member of the transaxle. This interactionbetween the hydraulically and mechanically appliedcomponents is explained in detail and supported witha graphic illustration. In addition, this section shows

the routing of fluid pressure to the individualcomponents and their internal operation when thecomponent applies or releases.

The sequence in which the components in this sectionhave been discussed coincides with their physicalarrangement inside the transaxle. This order closelyparallels the disassembly sequence used in the Hydra-matic 4T40-E Unit Repair Section located in Section 7of the appropriate Service Manual. It also correlateswith the components shown on the Range ReferenceCharts that are used throughout the Power Flowsection of this book. The correlation of informationbetween the sections of this book helps the user tomore clearly understand the hydraulic and mechanicaloperating principles for this transaxle.

APPLY COMPONENTS

Figure 15 15

APPLY COMPONENTS

Figure 1616

DIRECT &COAST CLUTCH

ASSEMBLY(105)

REVERSE INPUT CLUTCH

ASSEMBLY(102)

OIL SEALRING(403)

2ND CLUTCHHOUSING

DRIVEN SPROCKETSUPPORT ASSEMBLY

(95)STATIONARY

LINE PRESSURE

DIR

EC

T C

LUT

CH

FLU

ID

CO

AS

T C

LUT

CH

FLU

ID

2ND

CLU

TC

H F

LUID

LUB

E 1

FLU

ID

RE

VE

RS

E C

LUT

CH

FLU

ID

OIL SEALRING(500)

Driven Sprocket SupportDirect Clutch Apply FluidDirect clutch apply fluid travels through the driven sprocket supportto a hole in the input shaft, between the 2nd and 3rd oil seal rings(500), and into the direct clutch housing to apply the piston.Coast Clutch Apply FluidThis fluid travels through the driven sprocket support to a holein the input shaft, between the 3rd and 4th oil seal rings (500),and on to the coast clutch to apply the piston.

Worn or improperly installed oil seal rings can greatly affect theapply force and lubrication capabilities of the fluid in thetransaxle.

Damaged or leaking seals (500) can cause no third gear/slips inthird, or no coast clutch apply/slipping in all manual ranges.

Porosity or leaking 2nd clutch piston seals can cause no second/slips in second.

Damaged or leaking seals (403) can cause no reverse gear/slipsin reverse.

Along with being the housing for the 2nd clutch and a supportfor the driven sprocket, the driven sprocket support acts as astationary fluid routing component, delivering fluid to rotatingcomponents. This is accomplished through a series of passagesand seals within the sprocket support, the reverse clutch assemblyand the direct and coast clutch assembly.

Reverse Clutch Fluid PassageReverse clutch fluid flows through the driven sprocket support,exits through a hole, between the oil seal rings (403), and entersthe reverse clutch housing to apply the reverse clutch.

Lube 1 Fluid PassagesLube 1 fluid travels through the driven sprocket support andexits through a hole to lubricate bushings and parts in thisregion of the transaxle.

Lube 1 fluid also travels through another passage in the drivensprocket support to a hole, between the first and second oil sealrings (500), in the input housing shaft. This fluid lubricates thebushings in this area of the transaxle (see Lubrication Pointspage 104).

APPLY COMPONENTS

Figure 17 17


(95)

96 97

98

99404 405 406


(401)

WAVEDPLATE

(96)

STEELCLUTCHPLATE

(97)

BACKINGPLATE

(99)

FIBERCLUTCHPLATE

(98)

SPRINGASSEMBLY

(405)

OILSEALRING(403)

SPRINGRETAINING

RING(406)

LUBE 1PASSAGE

COASTCLUTCH

FLUIDPASSAGE

DIRECTCLUTCH

FLUIDPASSAGE

REVERSECLUTCH

FLUIDPASSAGE

2NDCLUTCH

FLUID

PISTONASSEMBLY

(404)

2ND CLUTCH RELEASE:The 2nd clutch releases whenever thetransaxle shifts into First gear, or whenthe selector lever is moved into the Park,Reverse, or Neutral ranges. As the 2ndclutch releases, 2nd clutch fluid pressurebetween the 2nd clutch piston assemblyand driven sprocket support exhauststhrough the support. In the absence offluid pressure, force from the spring

assembly causes the 2nd clutch piston tomove away from the clutch plates. Thepiston movement causes the clutch platesto lose contact with the backing platethereby releasing the 2nd clutch.

Component failure can cause nosecond/slips in second.

2ND CLUTCH:The 2nd clutch assembly (404-406 &96-99), located between the drivensprocket support (401) and the reverseclutch housing and race assembly (102),is applied whenever the transaxle isoperating in Overdrive Range Second,Third or Fourth gear. It is also appliedin Manual Second Range-Second gearand Third gear, Manual Third Range-Second and Third gear and Manual FirstRange-Second and Third gear.2ND CLUTCH APPLY:To apply the 2nd clutch, 2nd clutch fluidis routed into the driven sprocket support(401) behind the 2nd clutch pistonassembly (404). Fluid pressure movesthe piston and compresses the springassembly (405). The piston continues tomove until it compresses the 2nd clutchwaved plate (96) and holds the fiberplates (98) and steel plates (97) againstthe backing plate (99).When fully applied, the 2nd clutchprovides power through the planetary gearsets by holding the 2nd roller clutch cam(451) through the internal teeth on thefiber clutch plates. (The external teethon the steel clutch plates are splined intothe transaxle case.) This arrangementallows Second gear by redirecting powerthrough the reaction carrier.

APPLY COMPONENTS

Figure 1818

450 451 454452

*ROLLER CLUTCH IS VIEWED FROM THIS DIRECTION

OVERDRIVE RANGE - THIRD GEAR

OVERDRIVE RANGE - SECOND GEAR

*PREVENTEDFROM ROTATING

IN CLOCKWISE DIRECTION

REVERSECLUTCH

HOUSING(454)

ROLLERCLUTCH

RETAINER(450)

ROLLERCLUTCH

CAM(451)

ROLLERCLUTCH

ASSEMBLY(452)

HELD

HELD

HELD

ROLLER CLUTCHOVERRUNNING

(INNER RACE)REVERSECLUTCH

HOUSING(454)

ROLLERCLUTCH

ASSEMBLY(517)

ROLLERCLUTCH

CAM(451)

ROLLER CLUTCHHOLDING

(INNER RACE)REVERSECLUTCH

HOUSING(454)

ROLLERCLUTCH

ASSEMBLY(517)

ROLLERCLUTCH

CAM(451)

2ND ROLLER CLUTCH:The 2nd roller clutch (450-452), located between the drivensprocket support (401) and reverse clutch housing (454), holdsthe reverse clutch housing whenever the transaxle is operatingin Second gear.

2ND ROLLER CLUTCH ASSEMBLY HOLDING (the reactionsun gear):The 2nd clutch assembly (96-99 & 404-406) has fiber plates withinternal teeth splined to the 2nd roller clutch cam (451), and steelplates that are splined to the case. The 2nd roller clutch innerrace is part of the reverse clutch housing (454), which rotates inthe opposite direction of engine rotation during First gear opera-tion. When the 2nd clutch applies, internal teeth on the 2ndclutch fiber plates hold the 2nd roller clutch cam stationary. Thereverse clutch housing is then prevented from rotating in a direc-tion opposite to engine rotation because the rollers are forced towedge between the inner race and lowest part of the cam ramps.

When the 2nd roller clutch is mechanically locked up, it holdsthe reaction sun gear and shell assembly (529) through thereverse clutch housing. This arrangement directs power flow tothe reaction carrier assembly in Second gear.

2ND ROLLER CLUTCH ASSEMBLY RELEASED:The 2nd roller clutch assembly releases whenever the 2nd clutchreleases, or its rollers overrun (freewheel). An overrunningcondition occurs whenever the transaxle operates in Third gearwhere the 2nd clutch is not used for power flow through thegear sets. While operating in Third gear, the reverse clutchhousing rotates in the direction of engine rotation. When thisoccurs, the rollers are forced to rotate in the opposite directionwhich disengages the inner race from the outer cam. Therollers freewheel when this condition occurs.

Roller clutch damaged, not holding can cause no Overdriverange second/slips in second.

Note: Manual second will be available.

APPLY COMPONENTS

Figure 19 19

456 457 458 464463462

461

459

REVERSE CLUTCHHOUSING

(454)

460

EX

APPLIED RELEASED

REVERSECLUTCHAPPLYFLUID

LUBEPASSAGE

REVERSECLUTCH

HOUSING(454)

CONTROLORIFICE

WAVEDCLUTCHPLATE(460)

STEELCLUTCHPLATE(461)

SNAPRING(464)

FIBERCLUTCHPLATE(462)

SELECTIVEBACKING

PLATE(463)

SNAPRING(459)

SPRING &RETAINERASSEMBLY

(458)

CENTERRETAINER

& SEALASSEMBLY

(456)

PISTONASSEMBLY

(457)

lose contact with the backing platethereby releasing the reverse clutch.

With the clutch released, the reverseclutch ball capsule is forced off its seatby centrifugal force (rotation of thehousing). When the checkball unseats,residual reverse clutch fluid is forced tothe outer perimeter of the piston andexhausts through the checkball seat. (Ifthis fluid did not completely exhaust therecould be a partial apply, or drag of thereverse clutch plates.)Clutch not releasing can cause drive inneutral.

Clutch not applying can cause noreverse/slips in reverse.

REVERSE CLUTCH:The reverse input clutch assembly (102),is applied only when Reverse range isselected through the gear shift selectorlever, but the reverse clutch housing actsas part of the holding member of thereaction sun gear.

REVERSE CLUTCH APPLY (drives thereaction sun gear):To apply the reverse clutch, reverse clutchfluid is routed into the driven sprocketsupport (401) and follows a passagebetween the support and support sleeve.Reverse clutch fluid exits the support at afeed hole located between two oil seal rings(403) and enters the reverse clutch housingthrough feed holes located in the reverseclutch housing between the two bearingsurfaces. Reverse clutch fluid then entersthe inner apply area between the piston(457) and center retainer & seal assembly(456). The center retainer & seal assembly(456) has an orifice that allows fluid toenter the outer area of the piston. Thisorifice system allows a controlled rate ofapply to create a smoother shift feel.Reverse clutch fluid compresses the airtrapped in the outer piston area until fluidand air pressure seat the ball, which allowsfluid pressure to move the piston andcompress the spring & retainer assembly(458). The piston continues to move untilthe spring & retainer assembly compressesthe reverse clutch waved plate (460), andholds the steel clutch plates (461) and fiberclutch plates (462) against the selectivebacking plate (463).When fully applied, the reverse clutchcombines with the lo/reverse servoassembly (66-73) and lo/reverse band (111)to enable a reverse direction of rotationand power through the gear sets. (See Lo/Reverse Servo and Lo/Reverse Banddescription on page 25.)

REVERSE CLUTCH RELEASE:The reverse clutch releases whenever theselector lever is moved into another rangeand reverse clutch fluid, between thehousing and reverse clutch piston, isforced back through the feed holes intothe driven sprocket support. Releasefluid is allowed to slip by the outerportion of the center retainer & sealassembly (456) to allow a quick release.In the absence of fluid pressure, forcefrom the spring and retainer assemblycauses the reverse clutch piston to moveaway from the clutch plates. The pistonmovement causes the clutch plates to

SERVORETURNSPRING

(75)

SERVOSNAPRING(70)

SERVOPISTON

SEAL(78)

SERVOCOVER SEAL

(79)SERVOCOVER

(80)

SERVOAPPLY PIN

(76)

TRANSAXLECASE(51)

SERVOCUSHIONSPRING

(68)

SERVOPISTON

(77)

4TH BANDFLUID

INTERMEDIATEBANDFLUID

REVERSEINPUT CLUTCH

ASSEMBLY(102)INTERMEDIATE/

4TH BAND(100)

APPLY COMPONENTS

Figure 2020

REVERSEINPUT CLUTCH

ASSEMBLY(102)

INTERMEDIATE/4TH

BAND(100)

75

76

68

70

77

78

79

80

25

towards the intermediate/4th band. As theservo piston moves, it compresses the spring(75) until the pin travels far enough tocompress the intermediate/4th band. Theband is wrapped around the reverse inputclutch housing and when it is compressed, itholds the housing stationary.

When the transaxle is operating in Fourthgear and the intermediate/4th band is holdingthe reverse clutch housing, power is directedthrough the reaction carrier to the input carrierin order to provide an overdrive gear ratio.When the intermediate/4th band is appliedfor engine compression braking in ManualSecond Range-Second gear and Manual FirstRange-Second Gear, the band is used toprevent the reverse clutch housing fromrotating and overrunning the 2nd roller clutch.

INTERMEDIATE/4TH SERVO RELEASE:The intermediate/4th servo releases wheneverthe transaxle shifts out of Fourth gear into alower gear (excluding Manual Second Range-Second gear and Manual First Range-SecondGear). The band releases when 4th band fluidpressure or intermediate band fluid pressure,between the servo cover and servo piston, isrouted through the case to exhaust from thecircuit. The return spring forces the intermediate/4th servo piston away from the intermediate/4th band thereby releasing the band.

INTERMEDIATE/4TH SERVO ASSEMBLY:The intermediate/4th servo assembly (75-80),located in the bottom of the transaxle in thefront of the case (51), applies the intermediate/4th band (100) in Overdrive Range-Fourth gearor Manual Second Range-Second gear andManual First Range-Second Gear.

INTERMEDIATE/4TH BAND:The intermediate/4th band (100), locatedinside the case, is wrapped around the reverseinput clutch assembly (102) and held inposition by a machined area, in the case, inwhich the band anchor end fits. When theband is compressed by the intermediate/4thservo pin, it holds the reverse clutch housingin order to operate the transaxle in fourthgear, or for engine compression braking inManual Second Range-Second gear andManual First Range- Second Gear.

INTERMEDIATE/4TH SERVO APPLY(holds the reaction sun gear):To apply the intermediate/4th servo assemblyin Overdrive Range-Fourth gear, 4th bandfluid is routed through the valve body (18),channel plate (27), and case (51) to a feedhole located in the servo cover (80) at theouter apply area of the servo piston (77). InManual Second Range-Second gear andManual First Range-Second Gear,intermediate band fluid is routed through thevalve body (18), channel plate (27), and case(51) to a feed hole located in the servo cover(80) at the inner apply area of the servo piston(77). Intermediate or 4th band fluidpressure behind the piston,forces the servo pistonand pin to move

No servo apply cancause no 4th/slips in4th gear.

When fully applied, the direct clutchplates force the direct clutch housing andreaction carrier shaft shell (526) to rotateat turbine speed (depending on chainratio). The reaction carrier shaft shell issplined into the reaction carrier andcombines with the input sun gear (533)to power the gear sets at a 1:1 gear ratio.

DIRECT CLUTCH RELEASE:The direct clutch releases whenever thetransaxle downshifts into Second or Firstgear, or when the selector lever is movedinto the Park, Reverse, or Neutral ranges.Direct clutch fluid pressure between thepiston and housing exhausts through thesame passages that were used to apply the

clutch. In the absence of fluid pressure,force from the return spring & retainerassembly causes the direct clutch piston tomove away from the direct clutch applyplate. The piston movement causes theclutch plates to lose contact with the backingplate thereby releasing the direct clutch.

As direct clutch fluid exhausts through thedriven sprocket support, the direct clutchhousing checkball is forced off its seat bycentrifugal force (rotation of the housing).When the checkball unseats, residual directclutch fluid is forced to the outer perimeterof the piston and exhausts through thecheckball seat. (If this fluid did notcompletely exhaust there could be a partialapply, or drag of the direct clutch plates.)No direct clutch apply can cause firstand second gear only.

DIRECT CLUTCH:The direct clutch assembly (517-523),located inside the direct and coast clutchhousing (502), is applied whenever thetransaxle is operating in Overdrive Range-Third or Fourth gear and Manual First,Second or Third Range-Third gear.DIRECT CLUTCH APPLY (drives thereaction carrier):To apply the direct clutch, direct clutchfluid is routed into the driven sprocketsupport (95) and follows a passage betweenthe support and the support sleeve. Directclutch fluid exits the support at a feed holein the sleeve, passes through a holebetween the 2nd and 3rd oil sealrings (500) on the input shaft,through the shaft sleeve before

entering the directclutch housingbehind the directclutch piston (518). Direct clutch fluidpressure seats the direct clutch housingcheckball which allows fluid pressure tomove the piston and compress the returnspring & retainer assembly (519). Thepiston continues to move until it contactsthe direct clutch (apply) plate (521) andholds the direct clutch fiber plates (522)and steel plates (521) against the directclutch backing plate (523).

APPLY COMPONENTS

Figure 21 21

DIRECT & COASTCLUTCH AND INPUT SHAFT

HOUSING(502)

521

522

526523 517518 519 520

RETAINERRING(520)

REACTION CARRIERSHAFT SHELL

(526)

DIRECT CLUTCHSPRING & RETAINER

ASSEMBLY(519)

DIRECT CLUTCHPISTON

ASSEMBLY(518)

RETAININGRING(517)


HOUSING(502)

DIRECTCLUTCHBACKING

PLATE(523)

DIRECTCLUTCH

FIBER PLATE(522)

DIRECTCLUTCH

STEEL PLATE(521)

OIL SEALRING(500)

LUBEPASSAGE

DIRECTCLUTCHAPPLYFLUID

RETAINER & BALLASSEMBLY

APPLIED RELEASED

EX

APPLY COMPONENTS

Figure 2222


HOUSING(502)

RETAINERRING(507)

INPUT SUN GEARSHAFT &

INNER RACEASSEMBLY

(511)

COAST CLUTCHRELEASE SPRING

(505)

COAST CLUTCHSPRING RETAINER

(506)

COAST CLUTCHPISTON ASSEMBLY

(504)

RETAININGRING(517)


HOUSING(502)

INPUTSPRAGOUTERRACE(512)

COASTCLUTCH

FIBER PLATE(509)

COASTCLUTCH

STEEL PLATE(508)

OIL SEALRING(500)

LUBEPASSAGE

COASTCLUTCHAPPLYFLUID

RETAINER & BALLASSEMBLY

APPLIED RELEASED

EX

517510 511 512504 505 506 507 509

508

COAST CLUTCH APPLY (drives the input sun gear duringacceleration and allows engine compression braking duringdeceleration):To apply the coast clutch, coast clutch fluid is routed into thedriven sprocket support (95) and follows a passage between thesupport and an oil transfer sleeve. Coast clutch fluid then passesthrough a feed hole in the support and a feed hole between the3rd and 4th oil seal rings (500) on the input shaft. The fluid thenflows through an oil sleevein the input shaft to thecoast clutch housing.Coast clutch fluid thenenters the housingbetween the coast clutchpiston and coast clutchhousing. Apply fluid seatsthe checkball (located in thehousing) and moves the piston

COAST CLUTCH RELEASED:The coast clutch releases whenever the selector lever is movedinto Overdrive, Park, Reverse or Neutral ranges and coast clutchfluid pressure between the forward clutch piston (504) and coastclutch housing exhausts through the direct & coast clutch andinput shaft. In the absence of fluid pressure, force from thecoast clutch release spring assembly (505) causes the coast clutchpiston to move away from the clutch plates. The pistonmovement causes the clutch plates to lose contact with the inputsprag outer race thereby releasing the clutch.

As coast clutch fluid exhausts through the housing and drivensprocket support, the housing checkball is forced off its seat bycentrifugal force. When the checkball unseats, residual coast clutchfluid is forced to the outer perimeter of the piston and exhauststhrough the checkball seat. (If this fluid did not completely exhaustthere could be a partial apply or drag of the coast clutch plates.)

towards the coast clutch (apply)plate (508). The piston movesuntil it contacts the coast clutch(apply) plate and then forces thecoast clutch (fiber) plates (509)and steel plates (508) tocompress against the input spragouter race (512).When fully applied, the coastclutch holds the input sun gear shaftand inner race assembly, which is splined to the input sun gear.This arrangement prevents the input sprag elements fromoverrunning to provide engine compression braking in theManual ranges.

COAST CLUTCH:The coast clutch assembly (504-512 & 517), located inside the direct and coastclutch input shaft housing (502), is applied whenever the transaxle is operating ina Manual Range (Refer to Range Reference Chart on page 11).The coast clutch is responsible for holding the mechanical link from the gearsetsto the engine in all manual ranges to achieve engine compression braking. InOverdrive Ranges First, Second and Third the transaxle is allowed to coast(through the input sprag overrunning) when the throttle is reduced and vehiclespeed is greater than engine speed.

No coastclutch applycan causeno enginebraking inall manualranges.

511 512 514 515 514 516 533

Figure 23 23

APPLY COMPONENTS

RETAININGRING(516)

INPUTSUN GEAR

(533)

INPUT SUN GEARSHAFT & INNER RACE

ASSEMBLY(511)

SPRAG CLUTCHEND BEARING

(514)

RETAININGRING(517)

INPUT SPRAGOUTER RACE

(512)

INPUT SPRAGASSEMBLY

(515)

OUTERRACE(512)

INNERRACE(511)

INPUTSPRAG

(515)

INPUT SPRAGCLUTCH

OVERRUNNING

SPRAG (515) RELEASES (OVERRUNS) WHENINNER RACE (511) (SPLINED TO INPUT SUN GEAR)ROTATES FASTER THAN OUTER RACE (512)

OUTERRACE(512)

INNERRACE(511)

INPUTSPRAG

(515)INPUT SPRAG

CLUTCHHOLDING/DRIVING

OUTER RACE (512) HELD - SPRAG (515)FORCES INNER RACE (511) TO ROTATE ATINPUT HOUSING SPEED

SPRAG CLUTCH IS VIEWEDFROM THIS DIRECTION

INPUT SPRAG:The input sprag assembly (515), located between the input spragouter race (512) [splined to the direct & coast clutch and inputshaft housing (502)] and the input sun gear shaft & inner raceassembly (511), drives (transfers torque) the input sun gear (533)in all forward gear ranges (except 4th gear) in order to transmitpower to the gear sets. The sprag clutch is also designed to allowthe vehicle to coast in all overdrive gear ranges (except 4th gear).

INPUT SPRAG ASSEMBLY HOLDING(drives the input sun gear):The outer race (512) of the input sprag is splined to the direct &coast clutch and input shaft housing (502). The inner race is partof the input sun gear shaft assembly with the input sun gearsplined to the other end. When the engine is running the directand coast clutch and input shaft housing is always rotating. Theinput sprag holds when the housing is rotating, but is only effectivewhen the transaxle is in the overdrive gear ranges (except 4thgear). In the manual ranges the coast clutch is applied andtransfers the torque. When the input sprag holds, it drives theinput sun gear in order to direct power flow through the gear sets.

INPUT SPRAG RELEASED(allows coasting in overdrive gear ranges):The input sprag assembly releases (overruns) whenever the vehiclespeed is greater than engine speed (occurs during decelerationand in 4th gear). This is to allow coasting instead of enginebraking when in the overdrive gear ranges (except fourth gear).An overrunning condition occurs only in the Overdrive Rangeswhen the input sun gear (input sprag inner race) rotates fasterthan the outer race. The faster rotation of the inner race causesthe sprag elements to pivot and disengage with the outer race.

Input sprag clutch failure, not holding can cause no first,second or third gear/slips in first, second or third gear.

APPLY COMPONENTS

Figure 2424

FORWARD CLUTCHHOUSING

(609)

600 601 602 608607606605604

603

RELEASEDAPPLIED

EX

FORWARDCLUTCHAPPLYFLUID

FORWARDCLUTCH

HOUSING(609)

SNAPRING(600)

RETURNSPRING

ASSEMBLY(606)

FIBERCLUTCHPLATE(602)

STEELCLUTCHPLATE(603)

CLUTCHBACKING

PLATE(601)

WAVEDCLUTCHPLATE(604)

PISTONASSEMBLY

(607)

INNER SEALAND

SLEEVEASSEMBLY

(608)

SNAPRING(605)

CONTROLORIFICE

FORWARD CLUTCH:The forward clutch assembly (600-608),located inside the forward clutch housing(609), is applied whenever the transaxleis operating in any forward range.

FORWARD CLUTCH APPLY ( holdsthe input internal gear/drives thereaction carrier):To apply the forward clutch, forwardclutch fluid is routed into the forwardclutch support (656) and follows a passagebetween the support and an oil transfersleeve. Forward clutch fluid then passesfrom a hole in the support, between theoil seal rings, into a feed hole in theforward clutch housing, located betweenthe two bearing surfaces. Forward clutchfluid then enters the inner apply areabetween the piston (607) and the seal andsleeve assembly (608). The seal andsleeve assembly (608) has an orifice thatallows fluid to enter the outer area of thepiston. This orifice system allows acontrolled rate of apply to create asmoother shift feel. Forward clutch fluidcompresses the air trapped in the outerpiston area until fluid and air pressureseat the ball, which allows fluid pressureto move the forward clutch piston (607).As the piston moves, it compresses theforward clutch return spring assembly(606) until legs on the piston contact andhold the forward clutch waved plate (604),steel plates (603), and fiber plates (602)against the backing plate (601).When fully applied, the forward clutchholds the input flange and forward clutchhub assembly (108) through the internalteeth on the fiber clutch plates. (Externalteeth on the steel clutch plates are splinedto the forward clutch housing.) In firstgear the forward clutch housing will be

clutch piston to move away from theclutch plates. The piston movementcauses the clutch plates to lose contactwith the backing plate, thereby releasingthe forward clutch.

With the clutch released, the forwardclutch housing ball capsule is forced offits seat by centrifugal force (rotation ofthe housing). When the checkball unseats,residual forward clutch fluid is forced tothe outer perimeter of the piston andexhausts through the checkball seat.

If this fluid did not completely exhaustthere could be a partial apply, or drag ofthe forward clutch plates.

held by the lo roller clutch assembly orthe lo/reverse band.

FORWARD CLUTCH RELEASED (nopower transmitted through the inputinternal gear):The forward clutch releases whenever theselector lever is moved into Park, Reverseor Neutral ranges (in Neutral the forwardclutch releases only below a certainvehicle speed) and forward clutch fluidbetween the piston and housing exhauststhrough the forward clutch support.Release fluid is allowed to slip by theouter portion of the lip seal to allow aquick release. In the absence of fluidpressure, force from the forward clutchreturn spring assembly causes the forward

Figure 25 25

APPLY COMPONENTS

66

67

68

69

70

71

72

73

25

FORWARD CLUTCHHOUSING

(609)

LO/REVERSEBAND(111)

ANCHORPIN(64)

SERVORETURNSPRING

(66)

SERVOSNAPRING(70)

SERVOPISTON

SEAL(71)

SERVOCOVERSEAL(72)

SERVOCOVER

(73)

SERVOAPPLY PIN

(67)

SERVOCUSHIONSPRING

(68)

SERVOPISTON

(69)

OIL FEED TUBEASSEMBLY

(83)

LO BANDFLUID

REVERSEFLUID

FORWARDCLUTCH

HOUSING(609)

LO/REVERSEBAND(111)

LO/REVERSE SERVO ASSEMBLY:The lo/reverse servo assembly (66-73),located in the bottom of the transaxle in therear of the case (51), applies the lo/reverseband in Park, Reverse and Neutral ranges,and Manual First Range - First gear.

LO/REVERSE BAND:The lo/reverse band (111), located insidethe case, is wrapped around the forwardclutch housing and held in position by thelo/reverse band anchor pin (64). Whenthe band is compressed by the lo/reverseservo pin, it holds the forward clutchhousing stationary. [Note: The band isnot the primary holding member inManual First Range - First gearacceleration operation (Refer to lo rollerclutch, page 26.)]LO/REVERSE SERVO APPLY (holds theinput internal gear in conjunction withthe forward clutch/holds the reactioncarrier):To apply the lo/reverse servo assembly,reverse and/or lo band fluid is routed througha feed hole in the channel plate (27) to thebottom of the case (51) to the oil feed tubeassembly (83). Fluid then flows through

either the reverse or lo band feed tube to theservo cover (73). Reverse fluid enters theouter portion of the piston and lo band fluidenters the inner portion of the piston. Fluidpressure fills the cavity(s) between the servopiston and cover and forces the servo piston(69) and pin (67) to move towards the lo/reverse band (111). As the lo/reverse servopiston moves, it compresses the return spring(66) until the pin travels far enough tocompress the lo/reverse band. When theband compresses, it holds the forward clutchhousing stationary.When the transaxle is operating in Park orNeutral ranges, the lo/reverse band is theonly component holding the forward clutchhousing. The reason for applying the bandis to hydraulically and mechanicallyprepare the transaxle for a smooth garageshift (range selection from Park or Neutralinto Reverse). In Manual First Range -First gear, the lo/reverse band is appliedfor engine compression braking.LO/REVERSE SERVO RELEASE:The lo/reverse servo releases, allowing thelo/reverse band to release, whenever thetransaxle shifts out of P, R, N or ManualFirst Range - First Gear. The band releaseswhen reverse and/or lo band fluid pressurebetween the servo piston and servo coverexhausts from the circuit. Spring force from

the return spring moves the lo/reverseservo piston away from the lo/reverseband thereby releasing the band.

No apply of the lo/reverse servocan cause:

No reverse or slips in reverse No engine braking in Manual

First range.

APPLY COMPONENTS

Figure 2626

652609 656654

ROLLER CLUTCH IS VIEWED FROM THIS DIRECTION

STATIONARY

LO ROLLER CLUTCHHOLDING

LOROLLERCLUTCH

ASSEMBLY(652)

(CAM)FORWARDCLUTCH

SUPPORT(656)

FORWARDCLUTCH

HOUSING(609)

HELD

OVERDRIVE RANGE - FIRST GEAR

STATIONARY

LO ROLLER CLUTCHOVERRUNNING

LOROLLERCLUTCH

ASSEMBLY(652)

(CAM)FORWARDCLUTCH

SUPPORT(656)

FORWARDCLUTCH

HOUSING(609)

OVERDRIVE RANGE - SECOND GEAR

FORWARDCLUTCH

SUPPORT(656)

FORWARDCLUTCH

FLUID

FORWARDCLUTCH

FLUID

LUBE 2FLUID

LUBE 2FLUID

LO ROLLERCLUTCH

ASSEMBLY(652)

ROLLER CLUTCHINNER RACE ON

FORWARDCLUTCH

HOUSING(609)

OIL SEALRING(654)

LO ROLLER CLUTCH:The lo roller clutch assembly is made up of three majorcomponents: a cam which is part of the forward clutch support(656), the roller assembly (652), and the inner race which is partof the forward clutch housing (609). The lo roller clutch (652),located inside the forward clutch support, is the main componentthat holds the forward clutch housing whenever the transaxle isoperating in First gear (Overdrive

4t40e repair manual

Documents

hydramatic 4t40e transaxle

thespecific transaxle

gm powertrain publication

hydraulic control components

matic contentsintroduction

proper service publication

time of publication

electronic control components