4L80E Hydraulic Book

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4L80-E

HYDRA-MATIC

PREFACE

All information contained in this book is based on the latest data available

at the time of publication approval. The right is reserved to make product or

publication changes, at any time, without notice.

No part of any GM Powertrain publication may be reproduced, stored

in 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 of

Powertrain Group of General Motors Corporation. This includes all

text, illustrations, tables and charts.

The Hydra-matic 4L80-E Technician’s Guide is intended for automotive

technicians that are familiar with the operation of an automatic transaxle or

transmission. Technicians or other persons not having automatic transaxle

or transmission know-how may find this publication somewhat technically

complex if additional instruction is not provided. Since the intent of this

book is to explain the fundamental mechanical, hydraulic and electrical

operating principles, technical terms used herein are specific to the

transmission industry. However, words commonly associated with the

specific transaxle or transmission function have been defined in a Glossary

rather than within the text of this book.

The Hydra-matic 4L80-E Technician’s Guide is also intended to assist

technicians during the service, diagnosis and repair of this transmission.

However, this book is not intended to be a substitute for other General

Motors service publications that are normally used on the job. Since there

is a wide range of repair procedures and technical specifications specific to

certain vehicles and transmission models, the proper service publication

must be referred to when servicing the Hydra-matic 4L80-E transmission.

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The Hydra-matic 4L80-E Technician’s Guide is

another Powertrain publication from the Technician’s

Guide series of books. The purpose of this

publication, as is the case with other Technician’s

Guides, is to provide complete information on the

theoretical operating characteristics of this

transmission. Operational theories of the mechanical,

hydraulic and electrical components are presented in

a sequential and functional order to better explain

their operation as part of the system.

In the first section of this book entitled “Principles

of Operation”, exacting explanations of the major

components and their functions are presented. In

every situation possible, text describes component

operation during the apply and release cycle as well

as situations where it has no effect at all. The

descriptive text is then supported by numerous

graphic illustrations to further emphasize the

operational theories presented.

The second major section entitled “Power Flow”,

blends the information presented in the “Principles of

Operation” section into the complete transmission

assembly. The transfer of torque from the engine

through the transmission is graphically displayed on a

full page while a narrative description is provided on

a facing half page. The opposite side of the half page

contains the narrative description of the hydraulic fluid

as it applies components or shifts valves in the system.

Facing this partial page is a hydraulic schematic that

shows the position of valves, checkballs, etc., as they

function in a specific gear range.

The third major section of this book displays the

“Complete Hydraulic Circuit” for specific gear

ranges. Fold-out pages containing fluid flow

schematics and two dimensional illustrations of major

components graphically display hydraulic circuits.

This information is extremely useful when tracing

fluid circuits for learning or diagnosis purposes.

The “Appendix” section of this book provides

additional transmission information regarding

lubrication circuits, seal locations, illustrated parts

lists and more. Although this information is available

in current model year Service Manuals, its inclusion

provides for a quick reference guide that is useful to

the technician.

Production of the Hydra-matic 4L80-E Technician’s

Guide was made possible through the combined

efforts of many staff areas within the General Motors

Powertrain Division. As a result, the Hydra-matic

4L80-E Technician’s Guide was written to provide

the user with the most current, concise and usable

information available regarding this product.

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specific fluid circuits that enable the mechanical

components to operate. The mechanical power

flow is graphically displayed on a full size page

and is followed by a half page of descriptive text.

The opposite side of the half page contains the

narrative description of the hydraulic fluid as it

applies components or moves valves in the system.

Facing this partial page is a hydraulic schematic

which shows the position of valves, ball check

valves, etc., as they function in a specific gear

range. Also, located at the bottom of each half

page is a reference to the Complete Hydraulic

Circuit section that follows.

• The Complete Hydraulic Circuits section

(beginning on page 75) details the entire hydraulic

system. This is accomplished by using a fold-out

circuit schematic with a facing page two

dimensional fold-out drawing of each component.

The circuit schematics and component drawings

display only the fluid passages for that specific

operating range.

• Finally, the Appendix section contains a schematic

of the lubrication flow through the transmission,

disassembled view parts lists and transmission

specifications. This information has been included

to provide the user with convenient reference

information published in the appropriate vehicle

Service Manuals. Since component parts lists

and specifications may change over time, this

information should be verified with Service

Manual information.

First time users of this book may find the page layout

a little unusual or perhaps confusing. However, with

a minimal amount of exposure to this format its

usefulness becomes more obvious. If you are

unfamiliar with this publication, the following

guidelines are helpful in understanding the functional

intent for the various page layouts:

• Read the following section, “Understanding the

Graphics” to know how the graphic illustrations

are used, particularly as they relate to the

mechanical power flow and hydraulic controls

(see Understanding the Graphics page 6).

• Unfold the cutaway illustration of the

Hydra-matic 4L80-E (page 8) and refer to it as you

progress through each major section. This

cutaway provides a quick reference of component

location inside the transmission assembly and

their relationship to other components.

• The Principles of Operation section (beginning on

page 9A) presents information regarding the major

apply components and hydraulic control

components used in this transmission. This section

describes “how” specific components work and

interfaces with the sections that follow.

• The Power Flow section (beginning on page 47)

presents the mechanical and hydraulic functions

corresponding to specific gear ranges. This

section builds on the information presented in the

Principles of Operation section by showing

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OVERRUN CLUTCH ASSEMBLY (504–511) OIL PAN (28) CONVERTER PUMP ASSEMBLY STATOR ROLLER CLUTCH ASSEMBLY CONVERTER STATOR ASSEMBLY TORQUE CONVERTER ASSEMBLY (1) OIL PUMP ASSEMBLY (4) FOURTH CLUTCH ASSEMBLY (523–533) FORWARD CLUTCH ASSEMBLY (601–616) MAIN SHAFT (662) DIRECT CLUTCH ASSEMBLY (616–623) INTERMEDIATE CLUTCH ASSEMBLY (629–640) INTERMEDIATE SPRAG CLUTCH ASSEMBLY (624) MANUAL SHIFT SHAFT DETENT LEVER ASSEMBLY (711) FILTER ASSEMBLY (31) CASE ASSEMBLY (7) OVERDRIVE ROLLER CLUTCH ASSEMBLY (512) LOW ROLLER CLUTCH ASSEMBLY (644) OVERDRIVE CARRIER ASSEMBLY (514) OUTPUT CARRIER ASSEMBLY (661) REACTION CARRIER ASSEMBLY (651) REAR INTERNAL GEAR (666) OUTPUT SHAFT (671) TURBINE SHAFT (502) MANUAL SHIFT SHAFT (708) CONTROL VALVE ASSEMBLY (44) PARKING PAWL ACTUATOR ASSEMBLY (710) PRESSURE PLATE ASSEMBLY PRESSURE CONTROL SOLENOID (320) OUTPUT SPEED SENSOR ASSEMBLY (22) PARKING PAWL (703) CASE EXTENSION (19) SUN GEAR (650) SUN GEAR SHAFT (649) MANUAL 2-1 BAND ASSEMBLY (628) LOW AND REVERSE BAND ASSEMBLY (657) CONVERTER TURBINE ASSEMBLY INPUT SPEED SENSOR ASSEMBLY (22) PR ND 1 2 D ➤➤➤ MANUAL VALVE ➤ ➤ LO PRND43 PRND4 DRIVE REVALL SWITCHESN.O. DRIVE PRND43 REV LO PRND4 PRND4 TFP SWITCH ➤ ➤ ➤ ➤ PRESSURE CONTROL SOLENOID VALVE (320) EX TORQUE SIGNAL

TORQUE SIGNAL TORQUE SIGNAL

FILTERED ACTR FD ➤➤ FILTER (302) ➤ ➤ ➤ EXEXEX ACT FD LIMIT LINE LINE ACTUATOR FEED ORIFICED ACTUATOR FEED

➤ ➤ ➤ ➤ ➤ EX D321 EX PRND43 PRND43 PRN PRN PRN PRN PRN PRN PRND4 PRND4 ACTR FD LINE LO FIL TERED ACTUA TOR FEED

FILTERED ACTUATOR FEED

REVERSE DRIVE D 21 ➤ ➤ FILTER (317) LUBE PIPE (39) R EAR L UBE ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ACTUA TOR FEED ACTUA TOR FEED ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ CONV FD LINE

LINE (from Pump)

SUCTION EX BOOST PRESSURE REG TORQUE SIG LINE LINE LINE REVERSE AIR BLEED (210) ➤

ORIFICE CUP PLUG (236)

➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ PRESSURE TAP (24) ➤ ➤ ➤ ➤ 4TH CL FD 4TH CL FD 4TH CLUTCH 1-2 SIG ORIFICED EX EX ACTUATOR FEED PRN EX 2-3 DRIVEDRIVE 1-2 SIGNAL 1-2 SIGNAL 2-3 SIGNAL EX 1-2 SOL ON N.O. 1-2 SIGNAL ACTR FD REV REVERSE REV ➤ ➤ ➤➤ ➤ EX 2-3 DRIVE ACTUATOR FEED 2-3 SIGNAL EX 2-3 SIGNAL FBA PRND4 3RD CLUTCH FEED EX ORIFICED EX ➤ ➤ ➤ 2-3 SOL OFF N.O. ➤ ➤ ➤ ➤ ➤ 19 20 ➤ ➤ 4 15 5 FBA PRND43 MANUAL 2-1 BAND SERVO (55–60) ➤ ➤ ➤ 2-3 SHIFT VALVE 1-2 SHIFT VALVE 3-4 SHIFT 5 3 2 1 4 ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ OUTPUT SHAFT ASSEMBLY (671) HELD OUTPUT CARRIER ASSEMBLY (661) HELD PARKING PAWL (703) ENGAGED PARKING PAWL RETURN SPRING (705) PARKING PAWL ACTUATOR ASSEMBLY (710) OVERDRIVE INTERNAL GEAR DRIVEN FORWARD CLUTCH HOUSING (602) CONVERTER HUB TORQUE CONVERTER ASSEMBLY (1) PUMP ASSEMBLY (4) TURBINE SHAFT (502) OVERRUN CLUTCH HOUSING (504) OVERDRIVE SUN GEAR OVERDRIVE CARRIER ASSEMBLY (514) OVERDRIVE CARRIER PINION GEARS HELD TURBINE SHAFT (502) HELD OVERDRIVE ROLLER CLUTCH (512) HOLDING NO POWER TRANSMITTED TO DIFFERENTIAL ASSEMBLY 1 POWER FROM TORQUE CONVERTER (1) 2c OVERDRIVE ROLLER CLUTCH (512) HOLDING 2d OVERDRIVE CARRIER PINION GEARS (518) HELD 3 OVERDRIVE INTERNAL GEAR DRIVEN 4 POWERFLOW TERMINATED PARK Figure 46 50 (Engine Running) COM PLE TE HYD RAUL IC CIR CUIT PAGE 76 With the selector lever in the

Park (P) position, lin e pressu re from the oil pump is directed to the fo llowing: Pressure Regulator V alve(218):

Reg-ulates pump output (line pressure) according to the transmission requirements. W

hen pump output exceeds the dem and

of line pressure, fluid from the pressure regulator

PARK

HOW TO USE THIS BOOK

HYDRA-MATIC 4L80-E 8 Figure 6 Figure 47 51 PARK (Engine Running) 50B

RANGE REFERENCE CHART LARGE CUTAWAY VIEW

OF TRANSAXLE (FOLDOUT)

HALF PAGE TEXT FOR EASY REFERENCE TO BOTH PAGES

PAGE NUMBER — FOR REFERENCE TO FLUID FLOW SCHEMATIC

➤ ➤ ➤ ➤ (Engine Running) ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; CENTER LUBE CENTER LUBE CENTER LUBE COOLER COOLER CENTER LUBE COOLER ➤ 2ND CL

LOW & REVERSE BAND SERVO (61–74) CONV FD LINE LINE LINE SUCTION EX BOOST PRESSURE REG TORQUE SIG TORQUE SIGNAL LINE LINE REVERSE REVERSE REVERSE LO PRND43 PRND4 DRIVE REVSWITCHESALL

N.O. DRIVE DRIVE PRND43 REV LO PRND4 PRND4 TFP SWITCH PR N D 1 2 D MANUAL VALVE EX D321 EX PRND43 PRND43 DRIVE PRN PRND4 PRND4 ACTR FD LINE LO LO D 21 D 21 D 21 D 21D 21

REVERSE

➤ PRESSURES

INTAKE & DECREASE (SUCTION) CONVERTER & LUBE MAINLINE SOLENOID SIGNAL "ON" SOLENOID SIGNAL "OFF" ACCUMULATOR ACTUATOR FEED TORQUE SIGNAL

SUCTION

CONV CLUTCH SHIFT

➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ REG APPLY REGULATED APPLY APP/RET REL FRONT LUBE FRONT LUBE DRIVE DRIVE DRIVE OVERRUN CLUTCH OVERRUN CLUTCH OVERRUN CLUTCH APPL Y/RETURN RELEASE RELEASE RELEASE COOLER TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC ENABLE TCC ENABLE CONV LIMIT EX EX REG CONV FD EXTCC ENABL EX TCC SIGNAL PUMP ASSEMBLY (4) EXEXEX ACT FD LIMIT LINE ACTUA TOR FD PRESSURECONTROL SOLENOID VALVE (320) EX TORQUE SIGNAL TORQUE SIGNAL 4TH CL FD 4TH CL FD4TH CL PRN PRN 1-2 SIGNAL 1-2 SIGNAL ORIF EX 3-4 SHIFT ACTR FD TCC (PWM) SOLENOID VALVE (323)

REGULATED APPLYLINE

EX

EX TCC REG

ORIFICED REG APPLY FILTERED 2-3 DRIVE TCC SIGNAL EX EX 2-3 DRIVE DRIVE 1-2 SIGNAL 2-3 SIG EX 1-2 SHIFT VALVE 1-2 SOL ON N.O. 1-2 SIGNAL ACTR FD ACTUATOR FEED ORIFICED EX EX EX REVERSE REV REV ➤➤➤ 2-3 DRIVE ACTUATOR FEED 2-3 SIGNAL 2-3 SIGNAL 2-3 SIGNAL EX EX EX EX 2-3 SHIFT VALVE 2-3 SIGNAL 4TH CLUTCH FEED 4TH CLUTCH FEED FBA PRND4 PRND4 D21 3RD CLUTCH FEED EX ORIFICED EX ORIFICED EX ACCUMULATOR ACCUM LO LO DRIVE 4TH CLUTCH 4TH CLUTCH 4TH CLUTCH ORIFICED ACCUM #11 3RD CL 3RD/REV 3RD/REVERSE REV #7 LORBA

REAR BAND APPLY

RBA

REAR BAND APPL

Y #1 OVERRUN CLUTCH D321 D321 4TH CLUTCH ASSEMBLY (523–533) INTERMEDIATE CLUTCH ASSEMBLY & CENTER SUPPORT (629–640) FORWARD CLUTCH ASSEMBLY (602–616) OVERRUN CLUTCH ASSEMBLY (504–511) DIRECT CLUTCH ASSEMBLY (616–623) TORQUE CONVERTER (1) FIL TERED 2-3 DRIVE 2-3 DRIVE PRESSURE TAP (24) 3b 3a 2b 2c 4 OIL PAN (28) LINE APPLY/RETURN FRONT LUBE DRIVE

R CONV FD REG CONV FD

PUMP BODY (203) CASE (7) PUMP COVER (206) AIR BLEED (210) FILTER ASSEMBLY (31) FRONT OIL COOLER PIPE CONNECTOR (8) REAR OIL COOLER PIPE CONNECTOR (90) ACTUATOR FEED ORIFICED ACTUATOR FEED 5e 5d 42a 6 37a19 FIL

TERED ACTR FDFIL

TERED ACTR FD 14a 42b 2d ACTUA TOR FEED ACTR FD 21 20a 20b 5c 20c 2220d 46a45 22b 22a 43f 44a 39b 40 39a 40 40a 20e 20f 39c39d 19b39e42d42c #4 2ND CLUTCH 2ND CL 2ND CLUTCH 2ND CL DRIVE DRIVE 2-3 DRIVE 2-3 DRIVE 24c23 24b23 24a DRIVE DRIVE DRIVE DRIVE 26a27 2-3 DRIVE #9 REVERSE REV REVERSE REVERSE REVERSE 43g 43h 43d 19d24 19c 2ND CLUTCH DRIVE PRND4 ➤ ➤ FBA FBA

FRONT BAND APPL

Y 43e 17a 43b 5b 43c REV REV 23a PRND43 PRND43 PRND43 18a 18b 36b 36a 43a 19a 26b 4546b 45b 37b 4TH ACCUM 3RD ACCUM 4TH CL3RD CL 3RD CL EX ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ #2 2828a 26h 26g 26i 33a33b 26e 16b 26f 28 26j #3 31b 31c #8 34 34 #5 32 32 26d 26c #6 38 38 #10 37d 37c 2ND ACCUM ACCUMULA TOR ACCUM ACCUM ACCUMULATOR MANUAL 2-1 BAND SERVO (55–60) 31d 34b 37e 41a 16a 31a 34c33c 35a

FRONT BAND APPLY

ACCUMULA TOR ACCUM ACCUM LO LINE LINE LINE LINE LINE 45a FILTER (302) FILTER (75) FILTER (317) LUBE PIPE (39) 14d 14c 14b 84 9 24 CONVERTER FEED 5a 25a 30a 2a 37f34a CASE (7) ➤ ➤ ➤ ➤➤ ➤ CONV FD DRIVE DRIVE DRIVE 4TH CL 41 TORQUE SIG REV ACTR FD FIL T ACTR FD ACTUATOR FEED ACTUATOR FEED ACTUA TOR FEED REVERSE 3RD CL FD PRN 3RD CL FD 2-3 SOL OFF N.O. 3 2 5 6 4 7 LO LO 12 11 9 10 8 13 14 15 16 19 18 17 20 21 22 1 ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ 23 ORIFICE CUP PLUG (208) ORIFICE CUP PLUG(237) ORIFICE CUP PLUG (236) ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ 3RD/REVREVERSE REVERSE 3RD/REVERSE CENTER LUBE ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ REAR LUBE ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤

CONTROL VALVE BODY (44) GASKET (45) GASKET (48)CASE (7) SPACER PLATE (46) ACCUMULATOR HOUSING (51) ACCUMULATOR GASKET (47) 3RD ACCUMULATOR 4TH ACCUMULATOR ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ OFF NOTE: - INDICATES BOLT HOLES - NON FUNCTIONAL HOLES HAVE BEEN REMOVED FROM COMPONENT DRAWINGS TO SIMPLIFY TRACING FLUID FLOW. - DUAL PURPOSE PASSAGES HAVE CASE SIDE NUMBERS LISTED FIRST - EXHAUST FLUID NOT SHOWN

➤➤

➤

➤ PUMP BODY (203) (Pump Cover Side)

;; ;;;; ;;;; ;;;; ;; ;; ;; ;;; ;;; ;; ;; ;; ;; ; ; ;;;;;; ;;;;;; ;;;;;; ;;;;;; ;;; ;;; ;;; ; ; ;; ;;;; ;; ;; ;; 43 2 2 2 2 2 2 1 1 8 7 8 8 47 47 47 48 48 9 7 30 3 3 14 43 12 49 12 10 12 47 45 47 11 2 9 29 29 47 45 1 ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ;; CASE (7) (Control Valve Body Side) ACCUMULATOR HOUSING (51) 3 14 37 3734 34 14 20 2 5 5 5 43 43 43 43 19 19 2 2 2 41 41 42 42 39 39 44 44 42 42 3 33 18 45 25 23 23 37 37 36 31 33 34 34 40 40 30 26 26 47 45 26 28 24 24 35 22 22 16 16 37 39 5 43 44 1 13 12 12 1 14 43 19 2 3 40 30 47 45 31 17 20 20 24 50 47 47 14 28 47 47 47 17 (8) ➤ (24) ➤ (39)➤ (90) ➤ (75) ➤ ➤ ➤ #9 #5 #6 #3 #4 #1 #10 #8 GASKET (48) (Case to Spacer Plate) GASKET (47)

(Accumulator Housing to Spacer Plate)

➤ ➤ 14 14 38 37 32 34 47 23 16 30 26 26 25 26 26 40 3 3 37 37 37 2 3939 42 5 34 45 45 33 14 2 19 43 5 2 5 22 1818 36 36 37 31 26 17 26 26 31 31 34 28 24 23 43 35 3133 45 45 42 24 19 20 20 43 43 43 22 44 42 41 5 42 2 39 41 39 16 19 43 20 20 5 43 20 20 14 SPACER PLATE (46) 44a 42c 2d 41a 39d 16a 22a 5b39e 42d 5c 22b 43c 43b 43d 43e 20a 20b 20c/21 19b 19c 24/19d 46b/45 45b 42b 18b 33c 23a 36b 35a 24a 23/24b 43g 34c 31d 36a 37e 46a/45 18a 28a 26j/28 26h 17a 32a 34a 37f 26g 26e/32 34b 45a 40a 38a 14d 14c 26b 30a 26a/27 25a 5d 37c 3a 2c37b 37a/19 42a 2a 19a 5a 20e 20f 14b 2b 43a 39c 39a/40 3b/4 33b/34 31a 14a 5e/6 37d 39b/40 33a/34 20d/22 31c 31b 23/24c 43h 43f 26i/28 26f/32 26c/38 26d/38 47 16b/41 GASKET (45) (Spacer Plate to Control Valve Body)

18 14 20 20 5 2 19 19 2 42 16 43 39 4 237 3 37 5 25 27 30 14 14 26 38 38 3226 37 40 45 34 34 32 17 46 31 34 26 28 28 43 35 34 37 36 36 31 24 18 45 42 31 2333 19 19 43 22 5 5 42 39 43 43 41 39 24244 47 6 40 46 20 2122 22 41 41 43 20 43 14 24 ➤ ➤ ➤ ➤ ➤ ➤ ➤ CASE (7) (Pump Cover Side) ; ; ➤ ➤ ➤ 1 12 30 30 40 40 3 3 2 2 19 19 43 43 14 14 12 13 13 1 (8) (90) (9) 48 ➤ ➤ ;; ;; ;; ;; ; PUMP COVER (206) (Case Side) ➤ ➤ 48 48 12 30 40 3 19 43 14 45 1 2 45 45 4547 45 49 49 40 29 19 (210) ➤ ➤ ➤➤ (210) (239) 2 ➤ ➤ ➤➤ ➤ ➤ ➤ ; ; ;; ;; ;; ;; ;; ;; ;;; ;;; ;;;;; ;; ;;;;; ;;; ;; ;; ;;;;; ;;;;; ;;;;; ;;;;; ; ; ;;; ;;;;; ;; ;; ; ; PUMP COVER (206) (Pump Body Side)

(208) (237) (236) 8 1249 11 3 30 30 32 40 3247 1 19 43 14 2 14 43 47 1 2 2 7 88 7 8 2 45 43 10 7 48 48 9 9 29 12 10 11 45 1 ➤ ➤ ➤ ➤1 ➤ 2 ➤ 3 ➤24 ➤ 16 ➤ 17➤ 18 ➤ 10 ➤15 ➤ 422➤ ➤ 21 ➤ 23 ➤ 19 ➤ 20 ➤ 13 ➤ 12 ➤ 7 ➤ 14 ➤ 8 ➤9 ➤11 ➤ 6 ➤ 5 ➤ ➤ ➤ ➤ ➤

CONTROL VALVE BODY (44) (Case Side) 36 36 37 46 34 47 37 47 38 38 32 32 47 47 47 47 47 47 47 47 14 14 5 20 5 2 2 2 4519 19 30 30 27 14 14 14 2 2 42 26 45 453 40 6 37 16 16 43 18 41 39 26 26 28 47 4747 47 47 47 47 47 17 43 43 5 5 17 17 2 42 4219 19 39 41 42 45 45 45 4323 23 18 3631 31 24 21 33 35 46 21 21 5 19 5 43 47 47 47 45 47 47 44 47 18 18 40 34 34 47 42 25 41 22 47 47 50 47 43 43 20 4 2222 22 20 25 43 (39) ➤ #7 #11 (317) ➤ ➤ (302) ➤ 45

PARK (Engine Running)

FOLDOUT ➤ 77 Figure 75

Figure 74

76

FLUID FLOW SCHEMATIC — (FOLDOUT)

(Engine Running)

With the selector lever in

the Park (P

)

position, lin e pressure from th

e oil

pump is dire cted to the followin

g:

Pressure Regu lator Va

lve(218):

Reg-ulates pump ou tput (line pre

ssure)

according to the transmission requireme nts. When pump output ex ceeds the de mand of line pressu re, fluid from the pressure regu

lator PARK 324TH 333-4ACCUM 35OV ERRUN 37OVERRUN CLU TCH 38D2 40 3-2S IGNAL

FLUID FLOW THROUGH COMPONENTS (FOLDOUT)

COMPLETE ILLUSTRATED PARTS LIST

HALF PAGE TEXT AND LEGEND

➤

➤ ➤

(6)

UNDERSTANDING THE GRAPHICS

The flow of transmission fluid starts in the bottom

pan and is drawn through the filter, case assembly and

into the oil pump assembly. This is a basic concept of

fluid flow that can be understood by reviewing the

illustrations provided in Figure 2. However, fluid may

pass between the control valve body, spacer plate,

case and other components many times before reaching

a valve or applying a clutch. For this reason, the

graphics are designed to show the exact location where

fluid passes through a component and into other

passages for specific gear range operation.

To provide a better understanding of fluid flow in

the Hydra-matic 4L80-E transmission, the

components involved with hydraulic control and fluid

flow are illustrated in three major formats. Figure 3

provides an example of these formats which are:

• A three dimensional line drawing of the component

for easier part identification.

• A two dimensional line drawing of the component

• A graphic schematic representation that displays

valves, ball check valves, orifices and so forth,

required for the proper function of transmission in

a specific gear range. In the schematic drawings,

fluid circuits are represented by straight lines and

orifices are represented by indentations in a circuit.

All circuits are labeled and color coded to provide

reference points between the schematic drawing

and the two dimensional line drawing of the

components.

• Figure 4 (page 7B) provides an illustration of a

typical valve, bushing and valve train components.

A brief description of valve operation is also

provided to support the illustration.

• Figure 5 (page 7B) provides a color coded chart

that references different fluid pressures used to

operate the hydraulic control systems. A brief

description of how fluid pressures affect valve

operation is also provided.

Figure 2

MANUAL 2-1 BAND SERVO ASSEMBLY

(55-60)

LOW AND REVERSE BAND SERVO

ASSEMBLY (61-74)

CONTROL VALVE BODY SPACER PLATE GASKET

(48)

CONTROL VALVE BODY GASKET

(45)

TRANSMISSION FLUID PRESSURE MANUAL VALVE

POSITION SWITCH (40) LUBE OIL PIPE (39) OIL PAN (28) OIL FILTER ASSEMBLY (31) CONTROL VALVE ASSEMBLY (44) CONTROL VALVE BODY

SPACER PLATE (46) ACCUMULATOR HOUSING GASKET (47) 3RD AND 4TH CLUTCH ACCUMULATOR HOUSING (51) OIL PUMP ASSEMBLY (4) TORQUE CONVERTER ASSEMBLY (1) CASE ASSEMBLY (7)

(7)

;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; ;;;; CENTER LUBE CENTER LUBE CENTER LUBE COOLER COOLER CENTER LUBE COOLER ➤ 2ND CL

LOW & REVERSE BAND SERVO (61–74) CONV FD LINE LINE LINE SUCTION EX BOOST PRESSURE REG TORQUE SIG TORQUE SIGNAL LINE LINE REVERSE REVERSE REVERSE LO PRND43 PRND4 DRIVE REV ALL SWITCHES N.O. DRIVE DRIVE PRND43 REV LO PRND4 PRND4 TFP SWITCH P R N _D 1 2 D MANUAL VALVE EX D321 EX PRND43 PRND43 DRIVE PRN PRND4 PRND4 ACTR FD LINE LO LO D 21 D 21 D 21 D 21 D 21

REVERSE

➤

PRESSURES INTAKE & DECREASE (SUCTION) CONVERTER & LUBE MAINLINE SOLENOID SIGNAL "ON" SOLENOID SIGNAL "OFF" ACCUMULATOR ACTUATOR FEED TORQUE SIGNAL

SUCTION

CONV CLUTCH SHIFT

➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ REG APPLY REGULATED APPLY APP/RET REL FRONT LUBE FRONT LUBE DRIVE DRIVE DRIVE OVERRUN CLUTCH OVERRUN CLUTCH OVERRUN CLUTCH APPL Y /RETURN RELEASE RELEASE RELEASE COOLER TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC SIGNAL TCC ENABLE TCC ENABLE CONV LIMIT EX EX REG CONV FD EX TCC ENABL EX TCC SIGNAL PUMP ASSEMBLY (4) EX EXEX ACT FD LIMIT LINE ACTUA TOR FD PRESSURE CONTROL SOLENOID VALVE (320) EX TORQUE SIGNAL TORQUE SIGNAL 4TH CL FD 4TH CL FD 4TH CL PRN PRN 1-2 SIGNAL 1-2 SIGNAL ORIF EX 3-4 SHIFT ACTR FD TCC (PWM) SOLENOID VALVE (323)

REGULATED APPLY LINE

EX

EX TCC REG

ORIFICED REG APPLY FILTERED 2-3 DRIVE TCC SIGNAL EX EX 2-3 DRIVE DRIVE 1-2 SIGNAL 2-3 SIG EX 1-2 SHIFT VALVE 1-2 SOL ON N.O. 1-2 SIGNAL ACTR FD ACTUATOR FEED ORIFICED EX EX EX REVERSE REV REV ➤➤ ➤ 2-3 DRIVE ACTUATOR FEED 2-3 SIGNAL 2-3 SIGNAL 2-3 SIGNAL EX EX EX EX 2-3 SHIFT VALVE 2-3 SIGNAL 4TH CLUTCH FEED 4TH CLUTCH FEED FBA PRND4 PRND4 D21 3RD CLUTCH FEED EX ORIFICED EX ORIFICED EX ACCUMULATOR ACCUM LO LO DRIVE 4TH CLUTCH 4TH CLUTCH 4TH CLUTCH ORIFICED ACCUM #11 3RD CL 3RD/REV 3RD/REVERSE REV #7 LO RBA

REAR BAND APPLY

RBA

REAR BAND APPL

Y #1 OVERRUN CLUTCH D321 D321 4TH CLUTCH ASSEMBLY (523–533) INTERMEDIATE CLUTCH ASSEMBLY & CENTER SUPPORT (629–640) FORWARD CLUTCH ASSEMBLY (602–616) OVERRUN CLUTCH ASSEMBLY (504–511) DIRECT CLUTCH ASSEMBLY (616–623) TORQUE CONVERTER (1) FIL TERED 2-3 DRIVE 2-3 DRIVE PRESSURE TAP (24) 3b 3a 2b 2c 4 OIL PAN (28) LINE APPL Y/RETURN FRONT LUBE DRIVE R CONV FD REG CONV FD PUMP BODY (203) CASE (7) PUMP COVER (206) AIR BLEED (210) FILTER ASSEMBLY (31) FRONT OIL COOLER PIPE CONNECTOR (8) REAR OIL COOLER PIPE CONNECTOR (90) ACTUATOR FEED ORIFICED ACTUATOR FEED

5e 5d 42a 6 37a19 FIL

TERED ACTR FD FIL

TERED ACTR FD 14a 42b 2d ACTUA TOR FEED ACTR FD 21 20a 20b 5c 20c 2220d 46a45 22b 22a 43f 44a 39b 40 39a 40 40a 20e 20f 39c 39d 19b 39e 42d 42c #4 2ND CLUTCH 2ND CL 2ND CLUTCH 2ND CL DRIVE DRIVE 2-3 DRIVE 2-3 DRIVE 24c23 24b 23 24a DRIVE DRIVE DRIVE DRIVE 26a27 2-3 DRIVE #9 REVERSE REV REVERSE REVERSE REVERSE 43g 43h 43d 19d24 19c 2ND CLUTCH DRIVE PRND4 ➤ ➤ FBA FBA

FRONT BAND APPL

Y 43e 17a 43b 5b 43c REV REV 23a PRND43 PRND43 PRND43 18a 18b 36b 36a 43a 19a 26b 4546b 45b 37b 4TH ACCUM 3RD ACCUM 4TH CL3RD CL 3RD CL EX ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ #2 28 28a 26h 26 g 26i 33a33b 26e 16b 26f 28 26 j #3 31b 31c #8 34 34 #5 32 32 26d 26c #6 38 38 #10 37d 37c 2ND ACCUM ACCUMULA TOR ACCUM ACCUM ACCUMULATOR MANUAL 2-1 BAND SERVO (55–60) 31d 34b 37e 41a 16a 31a 34c 33c 35a

FRONT BAND APPLY

ACCUMULA TOR ACCUM ACCUM LO LINE LINE LINE LINE LINE 45a FILTER (302) FILTER (75) FILTER (317) LUBE PIPE (39) 14d 14c 14b 84 9 24 CONVERTER FEED 5a 25a 30a 2a 37f34a CASE (7) ➤ ➤ ➤ ➤➤ ➤ CONV FD DRIVE DRIVE DRIVE 4TH CL 41 TORQUE SIG REV ACTR FD FIL T ACTR FD ACTUATOR FEED ACTUATOR FEED ACTUA TOR FEED REVERSE 3RD CL FD PRN 3RD CL FD 2-3 SOL OFF N.O. 3 2 5 6 4 7 LO LO 12 11 9 10 8 13 14 15 16 19 18 17 20 21 22 1 ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ 23 ORIFICE CUP PLUG (208) ORIFICE CUP PLUG (237) ORIFICE CUP PLUG (236) ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ 3RD/REV REVERSE REVERSE 3RD/REVERSE CENTER LUBE ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ RE A R LU B E ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤

CONTROL VALVE BODY (44) GASKET (45) GASKET (48) CASE (7) SPACER PLATE (46) ACCUMULATOR HOUSING (51) ACCUMULATOR GASKET (47) 3RD ACCUMULATOR 4TH ACCUMULATOR ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ OFF

UNDERSTANDING THE GRAPHICS

PUMP COVER SIDE

CASE SIDE THREE DIMENSIONAL THREE DIMENSIONAL TWO DIMENSIONAL THREE DIMENSIONAL TWO DIMENSIONAL TWO DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION TWO DIMENSIONAL SPACER PLATE CASE SIDE THREE DIMENSIONAL TWO DIMENSIONAL THREE DIMENSIONAL CONTROL CONTROL VALALVE BODYVE BODY ASSEMBL ASSEMBLY (44)Y (44) CASE CASE ASSEMBL ASSEMBLY (7) OIL OIL PUMP BODY PUMP BODY (4) ACCUMULA ACCUMULATORTOR HOUSING HOUSING (51)

VALALVE BODYVE BODY SP SPACERACER PLA PLATETE (23) GASKET (47) GASKET (45) GASKET (48) _SPACER PLATE (46)

➤

CASE SIDE

(8)

FLUID PRESSURES

INTAKE & DECREASE (SUCTION) CONVERTER & LUBE

MAINLINE

SOLENOID SIGNAL “ON” SOLENOID SIGNAL “OFF” ACCUMULATOR ACUATOR FEED TORQUE SIGNAL EXHAUST DIRECTION OF FLOW ➤ ➤ ➤ ➤ ➤ A B

➤

➤ ➤ _A _B ➤

WITH EQUAL SURFACE AREAS ON EACH END OF THE VALVE, BUT FLUID PRESSURE "A" BEING GREATER THAN FLUID PRESSURE "B", THE VALVE

WITH THE SAME FLUID PRESSURE ACTING ON BOTH SURFACE "A" AND SURFACE "B" THE VALVE WILL MOVE TO THE LEFT. THIS IS DUE TO THE LARGER SURFACE

UNDERSTANDING THE GRAPHICS

TYPICAL BUSHING AND VALVE

Figure 4 ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ SPRING RETAINING PIN BORE PLUG VALVE BUSHING

EXHAUST FROM THE APPLY COMPONENT UNSEATS THE BALL CHECK VALVE, THEREFORE CREATING A QUICK RELEASE.

TO APPLY

COMPONENT _{APPLY FLUID SEATS}

THE BALL CHECK VALVE FORCING FLUID THROUGH AN ORIFICE IN THE SPACER PLATE, WHICH CREATES A SLOWER APPLY.

WITH SIGNAL FLUID PRESSURE GREATER THAN SPRING AND SPRING ASSIST FLUID PRESSURE THE VALVE MOVES OVER. WITH SIGNAL FLUID PRESSURE

EQUAL TO OR LESS THAN SPRING AND SPRING ASSIST FLUID PRESSURE THE VALVE REMAINS IN CLOSED POSITION.

BUSHING ➤ VALVE BODY SPACER PLATE RESTRICTING ORIFICE BALL CHECK VALVE RETAINING PIN BORE PLUG SPRING VALVE BUSHING VALVE BODY ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤➤ ➤ ➤ ➤➤ ➤ ➤ ➤ SPACER PLATE SIGNAL FLUID APPLY FLUID SPRING ASSIST FLUID EX ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ SPACER PLATE SIGNAL FLUID APPLY FLUID SPRING ASSIST FLUID EX ➤ ➤ ➤ ➤ ➤ ➤ ➤ NOTE: NOT ALL VALVES ARE

(9)

HYDRA-MATIC 4L80-E

OVERRUN CLUTCH ASSEMBLY (504–511) OIL PAN (28) CONVERTER PUMP ASSEMBLY STATOR ROLLER CLUTCH ASSEMBLY CONVERTER STATOR ASSEMBLY TORQUE CONVERTER ASSEMBLY (1) OIL PUMP ASSEMBLY (4) FOURTH CLUTCH ASSEMBLY (523–533) FORWARD CLUTCH ASSEMBLY (601–616) MAIN SHAFT (662) DIRECT CLUTCH ASSEMBLY (616–623) INTERMEDIATE CLUTCH ASSEMBLY (629–640) INTERMEDIATE SPRAG CLUTCH ASSEMBLY (624) MANUAL SHIFT SHAFT DETENT LEVER ASSEMBLY (711) FILTER ASSEMBLY (31) CASE ASSEMBLY (7) OVERDRIVE ROLLER CLUTCH ASSEMBLY (512) LOW ROLLER CLUTCH ASSEMBLY (644) OVERDRIVE CARRIER ASSEMBLY (514) OUTPUT CARRIER ASSEMBLY (661) REACTION CARRIER ASSEMBLY (651) REAR INTERNAL GEAR (666) OUTPUT SHAFT (671) TURBINE SHAFT (502) MANUAL SHIFT SHAFT (708) CONTROL VALVE ASSEMBLY (44) PARKING PAWL ACTUATOR ASSEMBLY (710) PRESSURE PLATE ASSEMBLY PRESSURE CONTROL SOLENOID (320) OUTPUT SPEED SENSOR ASSEMBLY (22) PARKING PAWL (703) CASE EXTENSION (19) SUN GEAR (650) SUN GEAR SHAFT (649) MANUAL 2-1 BAND ASSEMBLY (628) LOW AND REVERSE BAND ASSEMBLY (657) CONVERTER TURBINE ASSEMBLY INPUT SPEED SENSOR ASSEMBLY (22)

(10)

HYDRA-MATIC 4L80-E

CROSS SECTIONAL DRAWING

A cross sectional line drawing is typically the standard

method for illustrating either an individual mechanical

component or a complete transmision assembly.

However, unless a person is familiar with all the

individual components of the transmission,

distinguishing components may be difficult in this type

of drawing. For this reason, a three dimensional

perspective illustration (shown on page 8) is the primary

drawing used throughout this book.

The purpose for this type of illustration is to provide a

more exacting graphic representation of each component

understanding the cross sectional line drawing by

comparing the same components from the three

dimensional perspective illustration. In this regard it

becomes an excellent teaching instrument.

Additionally, all the illustrations contained in this book

use a color scheme that is consistent throughout this

book. In other words, regardless of the type of

illustration or drawing, all components have an assigned

color and that color is used whenever that component

is illustrated. This consistency not only helps to provide

for easy component identification but it also enhances

(11)

An automatic transmission is the mechanical

component of a vehicle that transfers power

(torque) from the engine to the wheels. It

accomplishes this task by providing a number

of forward gear ratios that automatically change

as the speed of the vehicle increases. The reason

for changing forward gear ratios is to provide

the performance and economy expected from

vehicles manufactured today. On the

performance end, a gear ratio that develops a

lot of torque (through torque multiplication) is

required in order to initially start a vehicle

moving. Once the vehicle is in motion, less

torque is required in order to maintain the

vehicle at a certain speed. Once the vehicle

has reached a desired speed, economy becomes

the important factor and the transmission will

shift into overdrive. At this point output speed

is greater than input speed, and, input torque

is greater than output torque.

Another important function of the automatic

transmission is to allow the engine to be

started and run without transferring torque to

the wheels. This situation occurs whenever

Park (P) or Neutral (N) range has been

selected. Also, operating the vehicle in a

rearward direction is possible whenever

Reverse (

R) range has been selected

(accomplished by the gear sets).

The variety of ranges in an automatic

transmission are made possible through the

interaction of numerous mechanically,

hydraulically and electronically controlled

components inside the transmission. At the

appropriate time and sequence, these

components are either applied or released and

operate the gear sets at a gear ratio consistent

with the driver’s needs. The following pages

describe the theoretical operation of the

mechanical, hydraulic and electrical components

found in the Hydra-matic 4L80-E transmission.

When an understanding of these operating

principles has been attained, diagnosis of these

transmission systems is made easier.

The transmission can be operated in any one of the

seven different positions shown on the shift

quadrant (Figure 8).

P – Park position locks the output shaft, enabling

the engine to be started while preventing the vehicle

from rolling either forward or backward. For safety

reasons, the vehicle’s parking brake should be used

in addition to the transmission “Park” position.

Because the output shaft is mechanically locked by a

parking pawl anchored in the case, Park position

should not be selected until the vehicle has come to

a complete stop.

R – Reverse enables the vehicle to be operated in a

rearward direction.

N – Neutral position enables the engine to start and

operate without driving the vehicle. If necessary, this

position should be selected to restart the engine while

the vehicle is moving.

D – Overdrive range should be used for all normal

driving conditions for maximum efficiency and fuel

GENERAL DESCRIPTION

Figure 8

PRINCIPLES OF OPERATION

economy. Overdrive range allows the transmission

to operate in each of the four forward gear ratios.

Downshifts to a lower gear, or higher gear ratio, are

available for safe passing by depressing the

accelerator or by manually selecting a lower gear

with the shift selector.

D – Manual Third can be used for conditions where

it may be desirable to use only three gear ratios.

These conditions include towing a trailer and driving

on hilly terrain. This range is also helpful for engine

braking when descending slight grades. Upshifts and

downshifts are the same as in Overdrive range for

first, second and third gears except that the

transmission will not shift into fourth gear.

2 – Manual Second adds more performance for

congested traffic and hilly terrain. It has the same

starting ratio (first gear) as Manual Third but prevents

the transmission from shifting above second gear. Thus,

Manual Second can be used to retain second gear for

acceleration and engine braking as desired. Manual

Second can be selected at any vehicle speed but will

not downshift into second gear until the vehicle speed

drops below approximately 100 km/h (62 mph).

1 – Manual First can be selected at any vehicle speed.

If the transmission is in third or fourth gear it will

immediately shift into second gear. When the vehicle

speed slows to below approximately 56 km/h (35 mph)

the transmission will then shift into first gear. This is

particularly beneficial for maintaining maximum

engine braking when descending steep grades.

P

R

N

D

₂

1 The Hydra-matic 4L80-E is a fully automatic four

speed rear wheel drive electronically controlled

transmission. It consists primarily of a four-element

torque converter, three planetary gear sets, a hydraulic

pressurization and control system, friction and

mechanical clutches.

The four-element torque converter contains a pump, a

turbine, a pressure plate splined to the turbine, and a

stator assembly. The torque converter acts as a fluid

coupling to smoothly transmit power from the engine

to the transmission. It also hydraulically provides

additional torque multiplication when required. The

pressure plate, when applied, provides a mechanical

“direct drive” coupling of the engine to the transmission.

The three planetary gear sets provide the four forward

gear ratios and reverse. Changing gear ratios is fully

automatic and is accomplished through the use of a

powertrain control module (PCM). The PCM receives

and monitors various electronic sensor inputs and uses

this information to shift the transmission at the

optimum time.

The PCM commands shift solenoid valves, within the

transmission, on and off to control shift timing. The

PCM also controls the apply and release of the torque

converter clutch which allows the engine to deliver

the maximum fuel efficiency without sacrificing

vehicle performance.

The hydraulic system primarily consists of a gear type

pump and a control valve body. The pump maintains

the working pressures needed to stroke the servos and

clutch pistons that apply or release the friction

components. These friction components (when applied

or released) support the automatic shifting qualities of

the transmission.

The friction components used in this transmission

consist of five multiple disc clutches and two bands.

The multiple disc clutches combine with three

mechanical components, two roller clutches and a sprag

clutch, to deliver five different gear ratios through

gear sets. The gear sets then transfer torque through

the output shaft and out to the drive axles.

(12)

MAJOR MECHANICAL COMPONENTS

TORQUE CONVERTER ASSEMBLY (1) TURBINE SHAFT (502) FORWARD CLUTCH HUB (613) _MAIN SHAFT (662) DIRECT CLUTCH ASSEMBLY (616-623) MANUAL 2-1 BAND ASSEMBLY (628) INTERMEDIATE SPRAG CLUTCH OUTERRACE (625) INTERMEDIATE CLUTCH ASSEMBLY (629-638) TRANSMISSION CASE (7) REACTION CARRIER ASSEMBLY (651) LOW AND REVERSE BAND ASSEMBLY (657) SUN GEAR (650) OUTPUT CARRIER ASSEMBLY (661) PARKING PAWL (703) PARKING PAWL ACTUATOR ASSEMBLY (710) SUN GEAR SHAFT (649) MANUAL 2-1 BAND SERVO ASSEMBLY (55-60) INTERMEDIATE SPRAG CLUTCH ASSEMBLY (624) CENTER SUPPORT ASSEMBLY (640) LOW ROLLER CLUTCH ASSEMBLY (644) LOW AND REVERSE BAND SERVO ASSEMBLY (61-74) MAIN SHAFT (662) REAR INTERNAL GEAR (666) OUTPUT SHAFT ASSEMBLY (671) PUMP ASSEMBLY (4) 4TH CLUTCH ASSEMBLY (523-533) OVERRUN CLUTCH ASSEMBLY (504-511) OVERDRIVE ROLLER CLUTCH (512) TURBINE SHAFT (502) OVERDRIVE CARRIER ASSEMBLY (514) FORWARD CLUTCH ASSEMBLY (601-614) DIRECT CLUTCH HUB (615) SPLINED TOGETHER SPLINED TOGETHER SPLINED TOGETHER SPLINED TOGETHER SPLINED INTO OUTPUT CARRIER ASSEMBLY (661)

(13)

COLOR LEGEND

MAJOR MECHANICAL COMPONENTS

The foldout graphic on page 10 contains a disassembled drawing of the major components used in the Hydra-matic 4L80-E transmission. This drawing, along with the cross sectional illustrations on page 8 and 8A, show the major mechanical components and their relationship to each other as a complete assembly. Therefore, color has been used throughout this book to help identify parts that are splined together, rotating at engine speed, held stationary, and so forth. Color differentiation is particularly helpful when using the Power Flow section for understanding the transmission operation.

The color legend below provides the “general” guidelines that were followed in assigning specific colors to the major components. However, due to the complexity of this transmission, some colors (such as grey) were used for artistic purposes rather than based on the specific function or location of that component.

Components held stationary in the case or splined to the case. Examples: Pump Assembly (4), 4th Clutch Housing (529) and Manual 2-1 Band Assembly (628). Also includes Roller Clutches and Sprag assemblies.

Components that rotate at engine speed. Examples: Torque Converter Assembly (1) and Oil Pump Drive (205) and Driven (204) Gears.

Components that rotate at turbine speed. Examples: Converter Turbine, Turbine Shaft (502) and Overdrive Carrier Assembly (514).

Components that rotate at transmission output speed. Examples: Output Shaft Assembly (671) and Output Carrier Assembly (661).

Components such as the Stator in the Torque Converter (1), Overrun Clutch Housing Assembly (504), and Reaction Carrier Assembly (651).

Components such as the Forward Clutch Housing Assembly (602).

Forward Clutch Hub (613), Main shaft (662) and Rear Internal Gear (666).

Components such as the Direct Clutch Housing (623) and Intermediate Clutch Sprag Outer Race (625).

Accumulators, Servos and Bands.

All bearings and bushings.

(14)

COLOR LEGEND

APPLY COMPONENTS

The Range Reference Chart on page 11, provides another valuable source of information for explaining the overall function of the Hydra-matic 4L80-E transmission. This chart highlights the major 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 each major component that was previously discussed. If a component is active in a specific gear range, a word describing its activity will be listed in the column below that component. The row where the activity occurs corresponds to the appropriate transmission range and gear operation. An abbreviated version of this chart can also be found at the top of the half page of text located in the Power Flow section. This provides for a quick reference when reviewing the mechanical power flow information contained in that section.

(15)

RANGE REFERENCE CHART

OVERDRIVE MANUAL INTERMEDIATE LOW LOW AND

RANGE GEAR 1-2 SHIFT 2-3 SHIFT FOURTH OVERRUN ROLLER FORWARD DIRECT 2-1 SPRAG INTERMEDIATE ROLLER REVERSE

SOLENOID SOLENOID CLUTCH CLUTCH

CLUTCH CLUTCH CLUTCH BAND CLUTCH CLUTCH CLUTCH BAND

P-N

ON OFF HOLDING

R

REVERSE ON OFF HOLDING APPLIED APPLIED

1st ON OFF HOLDING APPLIED * HOLDING

D

2nd OFF OFF HOLDING APPLIED HOLDING APPLIED OVERRUNNING

3rd OFF ON HOLDING APPLIED APPLIED OVERRUNNING APPLIED OVERRUNNING

4th ON ON APPLIED OVERRUNNING APPLIED APPLIED OVERRUNNING APPLIED OVERRUNNING

1st ON OFF APPLIED HOLDING APPLIED * HOLDING

D

2nd OFF OFF APPLIED HOLDING APPLIED HOLDING APPLIED OVERRUNNING

3rd OFF ON APPLIED HOLDING APPLIED APPLIED OVERRUNNING APPLIED OVERRUNNING

2

1st ON OFF APPLIED HOLDING APPLIED * HOLDING

2nd OFF OFF APPLIED HOLDING APPLIED APPLIED HOLDING APPLIED OVERRUNNING

1

1st ON OFF APPLIED HOLDING APPLIED * HOLDING APPLIED

2nd OFF OFF APPLIED HOLDING APPLIED APPLIED HOLDING APPLIED OVERRUNNING

NOTE: DESCRIPTIONS ABOVE EXPLAIN COMPONENT FUNCTION DURING ACCELERATION.

*HOLDING BUT NOT EFFECTIVE @ THE SOLENOID'S STATE FOLLOWS A SHIFT PATTERN WHICH DEPENDS UPON VEHICLE

SPEED AND THROTTLE POSTION. IT DOES NOT DEPEND UPON THE SELECTED GEAR. ON = SOLENOID ENERGIZED

OFF = SOLENOID DE-ENERGIZED

HYDRAMATIC 4L80-E - GEAR RATIOS

FIRST 2.48 FOURTH .75

SECOND 1.48 REVERSE 2.08

THIRD 1.00

COLOR LEGEND

APPLY COMPONENTS

The Range Reference Chart on page 11, provides another valuable source of information for explaining the overall function of the Hydra-matic 4L80-E transmission. This chart highlights the major 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 each major component that was previously discussed. If a component is active in a specific gear range, a word describing its activity will be listed in the column below that component. The row where the activity occurs corresponds to the appropriate transmission range and gear operation. An abbreviated version of this chart can also be found at the top of the half page of text located in the Power Flow section. This provides for a quick reference when reviewing the mechanical power flow information contained in that section.

(16)

TORQUE CONVERTER

CONVERTER HOUSING COVER ASSEMBLY (A) PRESSURE PLATE ASSEMBLY (C) TURBINE THRUST SPACER (B) TURBINE ASSEMBLY (F) DAMPER ASSEMBLY (D) THRUST BEARING ASSEMBLY (G) PRESSURE PLATE SPRING (E) THRUST BEARING ASSEMBLY (G) STATOR ASSEMBLY (H) CONVERTER PUMP ASSEMBLY (I) A F I G STATOR SHAFT (235) TURBINE SHAFT (502) CONVERTER HUB H B E D TORQUE CONVERTER:

The torque converter (1) is the primary component for transmittal of power between the engine and the transmission. It is bolted to the engine flywheel (also known as the flexplate) so that it will rotate at engine speed. Some of the major functions of the torque converter are: • to provide for a smooth conversion of torque from the

engine to the mechanical components of the transmission. • to multiply torque from the engine that enables the vehicle to achieve additional performance when required. • to mechanically operate the transmission oil pump (4)

through the converter hub.

• to provide a mechanical link, or direct drive, from the engine to the transmission through the use of a torque converter clutch (TCC).

The torque converter assembly is made up of the following five main sub-assemblies:

• a converter housing cover assembly (A) which is welded to the converter pump assembly (I).

• a converter pump assembly (I) which is the driving member.

• a turbine assembly (F) which is the driven or output member.

• a stator assembly (G) which is the reaction member located between the converter pump and turbine assemblies.

• a pressure plate assembly (C) splined to the turbine assembly to enable direct mechanical drive when appropriate.

CONVERTER PUMP ASSEMBLY AND TURBINE ASSEMBLY

When the engine is running the converter pump assembly acts as a centrifugal pump by picking up fluid at its center and discharging it at its rim between the blades (see Figure 12). The force of this fluid then hits the turbine blades and causes the turbine to rotate. As the engine and converter pump increase in RPM, so does the turbine.

PRESSURE PLATE, DAMPER AND CONVERTER HOUSING ASSEMBLIES

The pressure plate is splined to the turbine hub and applies (engages) with the converter cover to provide a mechanical coupling of the engine to the transmission. When the pressure plate assembly is applied, the amount of slippage that occurs through a fluid coupling is reduced (but not eliminated), thereby providing a more efficient transfer of

Torque converter failure could cause loss of drive and or loss of power. To reduce torsional shock during the apply of the pressure plate to the converter cover, a spring loaded damper assembly (D) is used. The pressure plate is attached to the pivoting mechanism of the damper assembly which allows the pressure plate to rotate independently of the damper assembly up to approximately 45 degrees. During engagement, the springs in the damper assembly cushion the pressure plate engagement and also reduce irregular torque pulses from the

(17)

TORQUE CONVERTER

STATOR

STATOR ROTATES FREELY STATOR HELD FLUID FLOW REDIRECTED

CONVERTER AT COUPLING SPEED FLUID FLOW FROM TURBINE CONVERTER MULTIPLYING FLUID FLOW TURBINE ASSEMBLY (F) CONVERTER PUMP ASSEMBLY (I) STATOR ASSEMBLY (H) Figure 12 STATOR ASSEMBLY

The stator assembly is located between the pump assembly and turbine assembly, and is mounted on a way roller clutch. This one-way roller clutch allows the stator to rotate in one direction and prevents (holds) the stator from rotating in the other direction. The function of the stator is to redirect fluid returning from the turbine in order to assist the engine in turning the converter pump assembly. At low vehicle speeds, when greater torque is needed, fluid from the turbine hits the front side of the stator blades (the converter is multiplying torque). At this time, the one-way roller clutch prevents the stator from rotating in the same direction as the fluid flow, thereby redirecting fluid to assist the engine in turning the converter pump. In this mode, fluid leaving the converter pump has more force to turn the turbine assembly and multiply engine torque. As vehicle speed increases and less torque is required, centrifugal force acting on the fluid changes the direction of the fluid leaving the turbine such that it hits the back side of the stator blades (converter at coupling speed). When this occurs, the roller clutch overruns and allows the stator to rotate freely. Fluid is no longer being redirected to the converter pump and engine torque is not being multiplied. 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.

(18)

TORQUE CONVERTER

APPLY

When the PCM determines that the vehicle is at the

proper speed for the torque converter clutch to apply

it sends a signal to the TCC (PWM) solenoid valve.

The TCC (PWM) solenoid valve then regulates line

fluid from the pump into the regulated apply passage.

The regulated apply fluid then feeds the apply fluid

passage and applies the torque converter. The apply

passage is located between the turbine shaft and the

stator shaft. The fluid flows between the shafts, then

passes into the torque converter on the apply side of

the pressure plate assembly. Release fluid is then

routed out of the torque converter between the turbine

shaft and the stator shaft.

Apply fluid pressure forces the pressure plate against

the torque converter cover to provide a mechanical

link between the engine and the turbine.

The TCC apply should occur in fourth gear (also

third gear in some applications), and should not apply

until the transmission fluid has reached a minimum

operating temperature of 8

°

C (46

°

F) and the engine

coolant temperature reaches 50

°

C (122

°

F).

For more information on TCC apply and release, see

Overdrive Range – Fourth Gear TCC Released and

Applied, pages 64–65.

RELEASE

When the torque converter clutch is released, fluid is

fed into the torque converter by the pump into the

release fluid passage. The release fluid passage is

located between the stator shaft (235) and the turbine

shaft (502). Fluid travels between the shafts and enters

the release side of the pressure plate at the end of the

turbine shaft. The pressure plate is forced away from

the converter cover and allows the torque converter

turbine to rotate at speeds other than engine speed.

The release fluid then flows between the friction

element on the pressure plate and the converter cover

to enter the apply side of the torque converter. The

fluid then exits the torque converter through the apply

passage, which is located between the torque

converter clutch hub and the stator shaft (235), and

enters the pump.

➤ APPLY FLUID RELEASE FLUID ➤➤ ➤➤ ➤➤ APPLY FLUID PRESSURE PLATE TORQUE CONVERTER ASSEMBLY (1) TURBINE SHAFT (502) APPLY FLUID RELEASE FLUID ➤➤ ➤➤ ➤ ➤ RELEASE FLUID PRESSURE PLATE TORQUE CONVERTER ASSEMBLY (1) TURBINE SHAFT (502)

No TCC apply can be caused by:

• TCC (PWM) solenoid valve assembly (323) malfunction. • TCC valve (223) stuck or binding

• TCC regulator apply valve (324) stuck or binding • Converter limit valve (214) stuck or binding • TCC enable valve (217) stuck or binding • Spacer plate and gaskets misaligned or incorrect

(19)

OVERRUN CLUTCH: The overrun clutch assembly is located in the overrun clutch housing (504). The external teeth on the reaction (steel) plates (508) are splined to the overrun clutch housing while the internal teeth on the fiber clutch plate assemblies (509) are splined to the overdrive carrier assembly (514). The overrun clutch is applied only when the shift selector lever is in a Manual gear range First, Second, or Third. OVERRUN CLUTCH APPLY: To apply the overrun clutch, overrun clutch fluid is fed through the oil pump hub to the inner hub of the overrun clutch housing. Feed holes in the inner hub allow fluid to enter the housing behind the overrun clutch piston (505). Overrun clutch fluid pressure seats the overrun clutch ball check valve (located in the housing) and moves the piston to compress the spring assembly (506) to cushion the apply. As fluid pressure increases, the piston compresses the clutch plates (steel and fiber) together until they are held against the overrun clutch backing plate (510). Also, the increase in fluid pressure forces any air in the overrun clutch fluid circuit to exhaust past the ball check valve, before it seats, to prevent excess cushion during clutch apply. When fully applied, the steel plates (508) and fiber plates (509) are locked together, thereby holding the overrun clutch housing and overdrive carrier together. This forces the housing and carrier to turn as one unit during engine compression braking in the Manual gear ranges.

OVERRUN CLUTCH RELEASE: To release the overrun clutch, overrun clutch fluid exhausts through the overrun clutch housing inner hub and into the oil pump hub, allowing pressure at the overrun clutch piston (505) to decrease. In the absence of fluid pressure, spring force from the spring assembly (506) moves the overrun clutch piston (505) away from the clutch pack. This disengages the steel plates (508) and the fiber plates (509) from the backing plate (510) and disconnects the overrun clutch housing from the overdrive carrier .

If inoperative the overrun clutch can cause loss of drive, no overrun braking - D3, No fourth gear - D4, engine stall and harsh shifts from D4 to D3, D2 or D1.

During the exhaust of overrun clutch fluid, the overrun clutch ball check valve, located in the overrun clutch housing, unseats. Centrifugal force, resulting from the rotation of the overrun clutch housing, forces residual overrun clutch fluid to the outside of the piston housing and past the unseated ball check valve. If this fluid did not completely exhaust from behind the piston, there could be a partial apply, or drag, of the overrun clutch plates. 4TH CLUTCH:

The 4th clutch assembly, located in the 4th clutch housing (529), is held stationary to the transmission case (7) by the 4th clutch housing bolt (26). The external teeth on the reaction (steel) plates (526) are splined to the 4th clutch housing while the internal teeth on the fiber clutch plate assemblies (525) are splined to the overrun clutch housing (504). The 4th clutch is applied only when the transmission is in Fourth gear to provide an overdrive gear ratio.

4TH CLUTCH APPLY:

To apply the 4th clutch, 4th clutch fluid is fed from the case, through the 4th clutch housing bolt (26) and behind the 4th clutch piston (528). 4th clutch fluid pressure forces the piston against the 4th clutch spring assembly (532) to cushion the apply. As fluid pressure increases, the piston compresses the clutch plates (steel and fiber) together until they are held against the 4th clutch backing plate (524).

When fully applied, the steel plates (526) and fiber plates (525) are locked together and held stationary by the 4th clutch housing. The internal teeth on the fiber plates hold the overrun clutch housing (504) stationary to prevent the overdrive sun gear from rotating.

The orifice cup plug (530) is pressed into the 4th lutch housing. Air in the 4th clutch fluid circuit s forced out the orifice when 4th clutch fluid ressure increases to prevent excess cushion during th clutch apply.

4TH CLUTCH RELEASE:

To release the 4th clutch, 4th clutch fluid exhausts through the 4th clut circuit, allowing pressure at the 4th clutch piston (528) to decrease. absence of fluid pressure, spring force from the spring assembly (532) the 4th clutch piston away from the clutch pack. This disengages th plates (526) and fiber plates (525) from the backing plate (524), allowing the overrun clutch housing and overdrive sun gear to rotate.

Plugged fourth apply passage, damaged clutch plates, return spring assembly or piston seals can cause no fourth/slips in fourth.

OVERRUN CLUTCH HOUSING (504) 511 510 509 508 507 506 505 OVERRUN CLUTCH BALL CHECK VALVE APPLIED RELEASED ➤ _➤ ➤ ➤ ➤ ➤ ➤ LUBE PASSAGE LUBE PASSAGE LUBE PASSAGE BACKING PLATE RETAINER RING (511) SPRING RETAINER RING (507) BACKING PLATE (510) OVERDRIVE SUN GEAR OVERDRIVE ROLLER CLUTCH INNER CAM FIBER CLUTCH PLATE ASSEMBLY (509) STEEL CLUTCH PLATE (508) OVERRUN CLUTCH HOUSING (504) OVERRUN CLUTCH PISTON ASSEMBLY (505) OVERRUN CLUTCH APPLY FLUID SPRING ASSEMBLY (506) FIBER CLUTCH PLATE ASSEMBLY (525) STEEL CLUTCH PLATE (526) INNER SEAL (527) 4TH CLUTCH ORIFICE (530) OUTER SEAL (531) SPRING ASSEMBLY (532) SPRING RETAINER RING (533) 4TH CLUTCH HOUSING BOLT (26) 4TH CLUTCH APPLY FLUID CASE (7) 4TH CLUTCH PISTON (528) BACKING PLATE RETAINER RING (523) 4TH CLUTCH HOUSING (529) 4TH CLUTCH BACKING PLATE (524) 533 529 532 528 524 523 525 526 530 4TH CLUTCH ASSEMBLY (523-533) 4TH CLUTCH APPLY FLUID PASSAGE

APPLY COMPONENTS

Figure 21 21 APPLY COMPONENTS Figure 20 20 APPLY COMPONENTS FUNCTIONAL DESCRIPTION

➤

BRIEF DESCRIPTION

➤

CUTAWAY VIEW

➤

DISASSEMBLED VIEW

➤

MATING OR RELATED COMPONENTS

➤

The Apply Components section is designed to explain

the function of the hydraulic and mechanical holding

devices used in the Hydra-matic 4L80-E transmission.

Some of these apply components, such as clutches

and bands, are hydraulically “applied” and “released”

in order to provide automatic gear range shifting.

Other components, such as a roller clutch or sprag

clutch, often react to a hydraulically “applied”

component by mechanically “holding” or “releasing”

another member of the transmission. This interaction

between the hydraulically and mechanically applied

components is then explained in detail and supported

with a graphic illustration. In addition, this section

shows the routing of fluid pressure to the individual

components and their internal functions when it

applies or releases.

The sequence in which the components in this section

have been discussed coincides with their physical

arrangement inside the transmission. This order

closely parallels the disassembly sequence used in

the Hydra-matic 4L80-E Unit Repair Section located

in Section 7 of the appropriate Service Manual. It

also correlates with the components shown on the

Range Reference Charts that are used throughout the

Power Flow section of this book. The correlation of

information between the sections of this book helps

the user more clearly understand the hydraulic and

mechanical operating principles for this transmission.

(20)

FIBER CLUTCH PLATE ASSEMBLY (525) STEEL CLUTCH PLATE (526) INNER SEAL (527) 4TH CLUTCH ORIFICE (530) OUTER SEAL (531) SPRING ASSEMBLY (532) SPRING RETAINER RING (533) 4TH CLUTCH HOUSING BOLT (26) 4TH CLUTCH APPLY FLUID CASE (7) 4TH CLUTCH PISTON (528) BACKING PLATE RETAINER RING (523) 4TH CLUTCH HOUSING (529) 4TH CLUTCH BACKING PLATE (524) 533 529 532 528 524 523 525 526 530 4TH CLUTCH ASSEMBLY (523-533) 4TH CLUTCH APPLY FLUID PASSAGE

APPLY COMPONENTS

4TH CLUTCH:

The 4th clutch assembly, located in the 4th clutch housing (529), is held stationary to the transmission case (7) by the 4th clutch housing bolt (26). The external teeth on the reaction (steel) plates (526) are splined to the 4th clutch housing while the internal teeth on the fiber clutch plate assemblies (525) are splined to the overrun clutch housing (504). The 4th clutch is applied only when the transmission is in Fourth gear to provide an overdrive gear ratio.

4TH CLUTCH APPLY:

To apply the 4th clutch, 4th clutch fluid is fed from the case, through the 4th clutch housing bolt (26) and behind the 4th clutch piston (528). 4th clutch fluid pressure forces the piston against the 4th clutch spring assembly (532) to cushion the apply. As fluid pressure increases, the piston compresses the clutch plates (steel and fiber) together until they are held against the 4th clutch backing plate (524).

When fully applied, the steel plates (526) and fiber plates (525) are locked together and held stationary by the 4th clutch housing. The internal teeth on the fiber plates hold the overrun clutch housing (504) stationary to prevent the overdrive sun gear from rotating.

The orifice cup plug (530) is pressed into the 4th clutch housing. Air in the 4th clutch fluid circuit is forced out the orifice when 4th clutch fluid pressure increases to prevent excess cushion during 4th clutch apply.

4TH CLUTCH RELEASE:

To release the 4th clutch, 4th clutch fluid exhausts through the 4th clutch fluid circuit, allowing pressure at the 4th clutch piston (528) to decrease. In the absence of fluid pressure, spring force from the spring assembly (532) moves the 4th clutch piston away from the clutch pack. This disengages the steel plates (526) and fiber plates (525) from the backing plate (524), thereby allowing the overrun clutch housing and overdrive sun gear to rotate.

Plugged fourth apply passage, damaged clutch plates, return spring assembly or piston seals can cause no fourth/slips in fourth.

(21)

OVERRUN CLUTCH HOUSING (504) 511 510 509 508 507 506 505 OVERRUN CLUTCH BALL CHECK VALVE APPLIED RELEASED ➤ ➤ _➤ ➤ ➤ ➤ ➤ LUBE PASSAGE LUBE PASSAGE LUBE PASSAGE BACKING PLATE RETAINER RING (511) SPRING RETAINER RING (507) BACKING PLATE (510) OVERDRIVE SUN GEAR OVERDRIVE ROLLER CLUTCH INNER CAM FIBER CLUTCH PLATE ASSEMBLY (509) STEEL CLUTCH PLATE (508) OVERRUN CLUTCH HOUSING (504) OVERRUN CLUTCH PISTON ASSEMBLY (505) OVERRUN CLUTCH APPLY FLUID SPRING ASSEMBLY (506)

APPLY COMPONENTS

OVERRUN CLUTCH:

The overrun clutch assembly is located in the overrun clutch housing (504). The external teeth on the reaction (steel) plates (508) are splined to the overrun clutch housing while the internal teeth on the fiber clutch plate assemblies (509) are splined to the overdrive carrier assembly (514). The overrun clutch is applied only when the shift selector lever is in a Manual gear range -First, Second, or Third.

OVERRUN CLUTCH APPLY:

To apply the overrun clutch, overrun clutch fluid is fed through the oil pump hub to the inner hub of the overrun clutch housing. Feed holes in the inner hub allow fluid to enter the housing behind the overrun clutch piston (505). Overrun clutch fluid pressure seats the overrun clutch ball check valve (located in the housing) and moves the piston to compress the spring assembly (506) to cushion the apply. As fluid pressure increases, the piston compresses the clutch plates (steel and fiber) together until they are held against the overrun clutch backing plate (510). Also, the increase in fluid pressure forces any air in the overrun clutch fluid circuit to exhaust past the ball check valve, before it seats, to prevent excess cushion during clutch apply.

When fully applied, the steel plates (508) and fiber plates (509) are locked together, thereby holding the overrun clutch housing and overdrive carrier together. This forces the housing and carrier to turn as one unit during engine compression braking in the Manual gear ranges.

OVERRUN CLUTCH RELEASE:

To release the overrun clutch, overrun clutch fluid exhausts through the overrun clutch housing inner hub and into the oil pump hub, allowing pressure at the overrun clutch piston (505) to decrease. In the absence of fluid pressure, spring force from the spring assembly (506) moves the overrun clutch piston (505) away from the clutch pack. This disengages the steel plates (508) and the fiber plates (509) from the backing plate (510) and disconnects the overrun clutch housing from the overdrive carrier.

During the exhaust of overrun clutch fluid, the overrun clutch ball check valve, located in the overrun clutch housing, unseats. Centrifugal force, resulting from the rotation of the overrun clutch housing, forces residual overrun clutch fluid to the outside of the piston housing and past the unseated ball check valve. If this fluid did not completely exhaust from behind the piston, there could be a partial apply, or drag, of the overrun clutch plates.

If inoperative the overrun clutch can cause loss of drive, no overrun braking - D3, No fourth gear - D4, engine stall and harsh shifts from D4 to D3, D2 or D1.

4L80E Hydraulic Book

4L80-E

HYDRA-MATIC

CONTENTS

PREFACE

All information contained in this book is based on the latest data available

at the time of publication approval. The right is reserved to make product or

publication changes, at any time, without notice.

No part of any GM Powertrain publication may be reproduced, stored

in 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 of

Powertrain Group of General Motors Corporation. This includes all

text, illustrations, tables and charts.

The Hydra-matic 4L80-E Technician’s Guide is intended for automotive

technicians that are familiar with the operation of an automatic transaxle or

transmission. Technicians or other persons not having automatic transaxle

or transmission know-how may find this publication somewhat technically

complex if additional instruction is not provided. Since the intent of this

book is to explain the fundamental mechanical, hydraulic and electrical

operating principles, technical terms used herein are specific to the

transmission industry. However, words commonly associated with the

specific transaxle or transmission function have been defined in a Glossary

rather than within the text of this book.

The Hydra-matic 4L80-E Technician’s Guide is also intended to assist

technicians during the service, diagnosis and repair of this transmission.

However, this book is not intended to be a substitute for other General

Motors service publications that are normally used on the job. Since there

is a wide range of repair procedures and technical specifications specific to

certain vehicles and transmission models, the proper service publication

must be referred to when servicing the Hydra-matic 4L80-E transmission.

The Hydra-matic 4L80-E Technician’s Guide is

another Powertrain publication from the Technician’s

Guide series of books. The purpose of this

publication, as is the case with other Technician’s

Guides, is to provide complete information on the

theoretical operating characteristics of this

transmission. Operational theories of the mechanical,

hydraulic and electrical components are presented in

a sequential and functional order to better explain

their operation as part of the system.

In the first section of this book entitled “Principles

of Operation”, exacting explanations of the major

components and their functions are presented. In

every situation possible, text describes component

operation during the apply and release cycle as well

as situations where it has no effect at all. The

descriptive text is then supported by numerous

graphic illustrations to further emphasize the

operational theories presented.

The second major section entitled “Power Flow”,

blends the information presented in the “Principles of

Operation” section into the complete transmission

assembly. The transfer of torque from the engine

through the transmission is graphically displayed on a

full page while a narrative description is provided on

a facing half page. The opposite side of the half page

contains the narrative description of the hydraulic fluid

as it applies components or shifts valves in the system.

Facing this partial page is a hydraulic schematic that

shows the position of valves, checkballs, etc., as they

function in a specific gear range.

The third major section of this book displays the

“Complete Hydraulic Circuit” for specific gear

ranges. Fold-out pages containing fluid flow

schematics and two dimensional illustrations of major

components graphically display hydraulic circuits.

This information is extremely useful when tracing

fluid circuits for learning or diagnosis purposes.

The “Appendix” section of this book provides

additional transmission information regarding

lubrication circuits, seal locations, illustrated parts

lists and more. Although this information is available

in current model year Service Manuals, its inclusion

provides for a quick reference guide that is useful to

the technician.

Production of the Hydra-matic 4L80-E Technician’s

Guide was made possible through the combined

efforts of many staff areas within the General Motors

Powertrain Division. As a result, the Hydra-matic