oil DATSUN B110 1973 Service Repair Manual

AUTOMATIC
TRANSMISSION

1

1

1

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CD

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4
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t

I

fA

TIl70

4
t
ill

pJrP

I

Transmission
ase

II
Governor
Tightening
torque
T
of

@T
0
5

to
0
7

2

Oil
pump
12

Output
shaft
bolts
and
nuts

kg
rn
ft
Ib
3
6

to
5
1

3
Front
clutch

13
Rear
xtcnsion

@T
0
8

to
1
0

@T
2
0

to
2
5

4
Band
brake
14

Oil

pan

@T
5
8
to
7
2
14
to
18

5
Rear
clutch
15
Control

valve
4
to
5

@T
1
3
to
1

8

6
Front

planetary
gt
ar

16

Input
shaft

@T
29

to
36
9
4
to

13

7
Rear

planetary
gear
17

Torque
converter
6
5
to
7
5

@T
0
55
to
0
75

8
One

way
clutch
18

Converter

housing

@T
47

to
54
4
0
to
5
4

9
Low
Reverse
brake
19
Drive

plate
0
6
h

Q
8

Q
T

0
25
to
0
35

10
Oil
distributor
4
3
to

5
8
1

9
to
2
5

Fig
AT
2
Cross
sectional
uiew

of
3N71
B
automatic
transmission

I

AT
3

l

t

CHASSIS

HYDRAULIC
CONTROL
SYSTEM

l
FUNCTIONS
OF
HYDRAULIC

CONTROL

UNIT

AND
VALVES

Oil

pump

Manual

linkage

Vacuum

diaphragm

Downshift
solenoid

Governor
valve

Control

valve

assembly

HYDRAULIC
SYSTEM
AND

MECHANICAL
OPERATION
CONTENTS

P

range
Park

R

range
Reverse

N

range
Neutral

D

range
Low

gear

D2
range
2nd

gear

D3
range
Top
gear

D

range
kick
down

2

range
2nd

gear

1
range
Low

gear

12
range
2nd

gear
AT
4

AT
4

AT
5

AT
5

AT
5

AT
5

AT

7

AT13
AT
14

AT
16

AT
18

AT
20

AT
22

AT
24

AT

26

AT
28

AT
30

AT
32

FUNCTIONS
OF

HYDRAULIC

CONTROL
UNIT

AND
VALVES

The

hydraulic
control

system
con

lain
a
oil

pump
for

packing
up
oil

from
the
oil

pan
through
the
oil

strainer
A

shift
control

is

provided
by

two

centrifugally
operated
hydraulic

Oil

pump

Manual

linkage

Vacuum

diaphragm

Downshift

solenoid

Governor
valve

Oil

pump

The
oil

pump
is
the

source
of

control
medium
in
other
words
oil

for
the
control

system

The
oil

pump
is
of

an
internal

involute

gear
type
The
drive
sleeve
is
a

part
of
the

torque
converter

pump
governors
on
the

output
shaft
vacuum

control

diaphragm
and
downshift

solenoid

These

parts
work

in

conjunc

tion

with
valves
in

the
valve

body

I

I
Control
valve

impeller
and
serves
to
drive

the

pump

inner

gear
with
the

drive
sleeve

direct

ly
coupled
with
the

engine
operation

The
oil
flows

through
the

following

route

Oil

pan
Oil
strainer
bottom

of
the

control

valve
Control
valve
lower

AT
4
assembly
located
in
the
base
of
the

transmission
The
valves

regulate
oil

pressure
and

direct
it

to

appropriate

transmission

components

I
Torque
converter

Front
clutch

Rear
clutch

Low

and
reverse

brake

Band
brake

Lubrication

body
suction

port
Transmission
case

suction

port
Pump
housing
suction

port

Pump
gear
space
Pump

housing
delivery

port
Transmission

case

delivery
port
Lower

body

delivery
port
Control
valve
line

pressure
circuit

AUTOMATIC

TRANSMISSION

Manual

linkage

The
hand
lever
motion

The
hand

lever
is
located

in
the
driver

s
com

part

men

mechanically
transmitted
from

the
remote
control

linkage
is
further

transmitted
to
the
inner
manual

lever

in

the
transmission

case
from
the

range

selector
lever
in

the

right
center

poc

tion

of
the

transmission
case

through

the
manual

shaft
The
inner

manual

lever
is

thereby
turned

A

pin
installed
on

the
bottom
of

the
inner
manual
lever
slides
the

manu

al

valve

spool
of
the

control
valve
and

thus
the

spool
is

appropriately
posi

lioned

opposing
to

each
select

position

The

parking
rod

pin
is

held
in
the

groove
on
the

top
of
the
inner

manual

plate
The

parking
rod

pin
operates
the

rod
at
p

range
and

operates
the

mechanical

lock

system

Moreover
the
above
described

manual
shaft
is

equipped
with
an

inhibitor
switch
A

rotor
inside
the

inhibitor
switch
rotates
in

response
to

each

range
When
the

range
is
selected

at
p
or
N
the

rotor
closes
the

starter

magnet
circuit
so
that
the

engine
can

be
started
When
the

range

is
selected

at
R
the

rotor
closes
the

back

up
lamp
circuit
and
the

back

up

lamp
lights

Vacuum

diaphragm

The
vacuum

diaphragm
is
installed

un
the
left

center

portion
of
the

transmission
case
The

internal
con

struction
of
the
vacuum

diaphragm
is

as
follows
A
rubber

diaphragm
forms

a

partition
in
the
center
The

engine

intake
manifold

negative
pressure
led

through
vacuum
tube
and

spring
force

are

applied
to
the
front
surface
of
the

rubber

diaphragm
and

atmospheric

pressure
is

applied
to
the
back
surface

A
difference
between
pressure

applied

to

the
front
and
back
surfaces
be

comes
a

vacuum
reaction
and
thus

the
throttle
valve
of
the

control
valve

inside
the
transmission
case
is

op

erated

When
accelerator

pedal
is

fully
de

pressed
and
the
carburetor
is

fully

upened
but
the

engine
speed
is
not
1

Housing

2
Cover

3

Outer
gear
AT071

4
Inner

gear

5
Crescent

Fig
AT
3
Oil

pump

1

Manual

plate

2

Inhibitor

switch
A
TOB7

3

Parking
rod

4
Manual

shaft

Fig
AT
4

Manuallinhage

To
intake
manifold

A

TOBB

Fig
A
T
5

Vacuum
diaphragm

iV

Down
shift
solenoid
i

KiCk
down

switch

A

TOB9

Fig
A
T
6

Downshift
solenoid

AT
5
sufficiently
increased
the
manifold

negative
pressure
lowers

becomes

similar
to
the

atmospheric
pressure

and
the

vacuum
reaction

increases

since

the
flow

velocity
of
mixture

inside
the
intake
manifold
is

slow

Contrarily
when
the

engine
speed

increases
and

the
flow

velocity
of

the

mixture

increases
or
when

the
carbure

tor
is
closed

the
manifold

negative

pressure
increases
becomes
similar
to

vacuum
and
the

vacuum
reaction

reduces

Thus
a

signal
to

generate
hydraulic

pressure
completely
suited
to

the

engine

loading
at
the

control
valve
is

transmitted
from

the
vacuum
dia

phragm
and

most
suitable

speed

change
timing
and
line

pressure
are

obtained
so

that
the
most

proper

torque
capacity
is

obtained

against
the

transmitting

torque

Downshift

solenoid

The
downshift

solenoid
is

of
a

magnetic
type
installed

on
the
left
rear

portion
of
the

transmiSsion
case

When

a

driver

requires
accelerating
power

and

depresses
the
accelerator

pedal

down
to

the

stopper
a

kick
down

switch

located
in
the

middle
of
the

accelerator
link
is

depressed
by
a

push

rod
the
kick
down
switch
closes
cur

rent
flows
to

the
solenoid
the
sole

noid

push
rod
is

depressed
the

down

shift
valve
of

the
control
valve
inside

the
transmission

case
is

depressed
and

the

speed
is

changed
forcedly
from

3rd
to
2nd
within
a

certain
vehi

cle

speed
limit

Note
As
the
kick
own

switch
closes

when
the
accelerator

pedal
is

depressed
from
7
8
to
IS
16
of

the
whole
stroke
the

accelera

tor

pedal
should
be

correctly

adjusted
and
fixed
so
as
to

afford

complete
stroke

The

arrangement
of
the
switch

differs

according
the
models
of

vehicle

Governor
valve

The

primary
and

secondary
gover

nor
valves
are
installed

separately
on

the

back
of
the
oil
distributor
on

the

I
transmission

output
shaft

They

op

erate
in
the
same

speed
as
that
of
the

output
shaft
In
other
wotds

they

operate
at

a

speed
in

proportion
to
the

vehicle

speed
To
those
valves
the

line

pressure
is

applied
as
the

input

ftom
the
control
valve

through
the

transmission
case
rear

flange
and
oil

distributor
The

governor
pressure
in

proportion
to
the

output
shaft

speed

vehicle

speed
is
led

to
the

shift

valve

of
the
control
valve

through

inverse

rou
te
as
the

output
and
thus

the

speed
change
and
the
line

pressure

are

controlled

Operation
of

secondary

governor
valve

The

secondary
valve
is
a
control

valve
which
receives

line

pressure
I

and

controls
the

governor
pressure

When
the
manual

valve
is

selected

D
2

or
1

range
line

pres

sure
is

applied
to
the

ring
shape
area
of

f
this

valve
from
circuit

I
and

this

valve
is

depressed
toward
the

center

side
Movement
of
this
valve
to
a

certain

position
closes
the
circuit

from

I
to

15

simultaneously
while
mak

ing
a

space
from
the

15
to
the
center

drain

port
and

pressure
in
the

circuit

IS
is

lowered

When

the
vehicle
is

stopped
and
the

centrifugal
force
of
this
valve
is
zero

the
valve
is

balanced
In
this
a

gover

nor

pressure
which
is
balanced
with

the

spring
force
occurs
on
the

15

When
the

vehicle
is

started
and
the

centrifugal
force
increases
this

valve

slightly
moves
to
the
outside
and

when

the

space
from

I
to
15

increases

space
from
the

15
to
the

drain

port
reduces

simultaneously
As

the
result

governor
pressure
of
the

15
increases

and
the

governor

pres

sure
is

balanced
with
the
sum
of

centrifugal
force
and
the

spring
force

The

governor

pressure
thus

changt
s
in

response
to
the

vehicle

speed

change

centrifugal
force

Operation
of

primary

governor

valve

The
valve
is

an
ON
OFF

valve

which
closes
the

governor

pressure

15

regulated
by
the

secondary

gover
CHASSIS

nor
valve
when
the
vehicle

speed

reaches
the

minimum

speed
and

when

the
vehicle

speed
exceeds
a
certain

level

open
the

governor
and
forwards

the

governor
pressure
15
to
the

control

valve

When
the

vehicle
is

stopped
the

governor

pressure
is

zero
However

when
the

vehicle
is

running
slowly

this
valve

is

depressed
to

the
center

side

and
the

groove
to

the

IS
is

closed
since
the

governor
pressure

applied
to
the

ring

shape
area
is

higher

than
the

centrifugal
force
of
this

valve

When
the

governor
speed
exceeds
cer

tain

revolution
the

governor

pressure

in
the
circuit
15
also

increases
How

ever
as
the

centrifugal
force
increases

and
exceeds

the

governor
pressure
this

valve

moves
toward
the
outside
and

the

governor
pressure
is
transmitted

to

the
circuit
15

Two
different

valves
are

employed

in
the

governor
so
that
it
will
inde

pendently
control

the

speed
at

high

speed
and
at

low

speed
That

is
within

the

low

speed

range
the

governor

pressure
is
not

generated
owing
to
the

primary
valve

whereas
at

the

high

speed
range
above
the

break

point
a

governor

pressure
regula
ted

by
the

sec0Hdary
valve
is

introduced

The
break

point
is
the

point
at

which
the

function
of
one

of
the

govp
rnors
is

transferred
to
the
other

whee

the

speed

changes
from

the

w

speed

range
to

the

high
speed

range

To
con
trol
valve

Governor

pressure

tiS

y
ID

t

4

From
control
valve

Line

pressure
I

J

I

Primary
governor

2
Secondar

governor

3
Governor
valve

body
AT090

4

Oil
distributor

5

Output
shaft

Fig
AT
7
Cross

sectional
view

of

governor

AT
6
AT091

Fig
A
T
B

Output
shaft
with
oil

distributor
and

governor

I
Oil

distributor

2

Governor
valve

body
AT092

3

Primary

governor

valve

4

Secondary

governor

valve

Fig
A

T

9

Exploded
uiew

of

gouernor

LIMITED

WARRANTY
Your

Hurst

product

warranted

per

table

below

Irom

dale
01

purchase

against

defects

materinl

and

workmanship

Dur
ing

this

period

luch

defects

will

be

repoired

the

product
will

be

chllnQl

d

at

Huut

option

without

charge

This

war
onty

does

damiilge

used

bv

milu

lI

alteration
negligence

ALL

IMPLIED

WARRANTIES

INCLUDING

BUT
NOT

LIMITED

TO

WARRANTIES

OF

FITNESS

AND

MER
CHANTABllITV

ARE

LIMITED

IN

DURATION

TO

A

PE
RIOO

ENDING

WITH

THE

PERIOD

OF

THE

CORRESPOND
ING

EXPRESS

LIMITED

WARRANTY

AS

SET

FORTH

BE
LOW

UNDER

NO

CIRCUMSTANCES

WILL

HURST

BE

RE
SPONSI8LE

FOR

INCIDENTAL

OR

CONseQUENTIAL
DAMAGES

ARISING

FADM

OR

IN

CONNECTION

WITH
THE

INSTALLATION

OR

USE

OF

ANY

HURST

PRODUCT
Some

tates

do

not

allow

limitations

on

how

long

implied
warranty

lasts

do

not

allow

for

tha

Axclusion

limitation

of
incidental

nnlequantial

damages

the

above

limitations
may

not

apply

to

you

This

Warranty

givlIs

you

specific

legal
righta

and

you

may

also

have

other

rights

which

Vpry

from
state

to

state

Return

of

the

Product

Registration

Card

nOt
nndition

precedent

Warranty

nvAraga

and

performance
HURST

WARRANTY

PERIODS

from

cJ

ffI

of

purch

lt
I
Shift

rs
Air

Shocks

12monttlt
12

OOOmil

or

12month1
whch

ver

lim
gOd

vl

12montl1s
12montl1s
12montl1s
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Tr

Rlmission

Oil

Coolers
Autom

tic

Tr

umitsion

P

rh
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f

rPloductt

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c

udinll
producrr

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rw

ingl
Bring

the

product

or

nd

it

pOttage

preplidf

Hurst
Performance

Inc

or

IIuthorized

doaler

If

you

end

the

product
pleas

write

letter

IIxplaining

the

01

your

difficulty
HURST

PERFORMANCE

INC
50

West

Street

Road
Warminnl
r

PennsylvlInlll18974
In

tha

ellenl

you

have

any

questions

rning

IInd
of

the

product

rning

pleese

write
Customer

Satisfaction

Depertment

lit

above

addreu
How

To

Get

Quick

Service
1

Peck

your

Hunt

product

r

nrefully

good

IriOn

with
plenty

of

newspape

s

u

celsior

padding

all

mund

it

and

till
lIly

Oamllge

transit

not

nv

red

by

the

warranty
2

Carefully

prinl

the

lrton

thlll

name

Ind

Iddrllu

01

Hurl
above

Don

t

forget

your

return

addreu
3

Put

I

tter

showing

desired

n

lIlope

addressed
HUrl

above

In

your

lettllr

plellSe

be

to

give

full
formation

such

date

and

place

of

purchase

your

full

name
IInd

address

and

the

reptllrS

d

sired
4

PASTE

ENVELOPE

TO

PACKAGE
S

Put

First

CIBst

stamp

nvelope

IInd

Parcel

Pall

stamps
package

then

mail

The

Post

Office

will

tell

yOU

the

proper
amount

of

postage

and

against

Iou

the

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Control

valve

assembly
AUTOMATIC
TRANSMISSION

Oil

from

pump

ru
nn

i

I
I
I
Throttle
valve

I

I

1
m
nn

I
Auxiliary
valve

I
Regulator
valve

j

Manual
valve

I

Uoe

pressure

Speed
change
L

I
Governor

valve

I
I
valve

J
1
1

Clutch
and
brake

Flow

chart
of

control
valve

system

The
control
valve

assembly
receives

oil

from
the

pump
and
the

individual

signals
from
the
vacuum

diaphragm

and
transmits
the
individual

line

pres

sures
to
the
transmission
friction

ele

ment

torque
converter
circuit
and

lubricating
system
circuit

as
the
out

puts
To
be

more

specifically
the
oil

from
the
oil

pump
is

regulated
by
the

regulator
valve
and
line

pressures
build

up
The
line

pressures
are
fed
out
from

the
control
valve

assembly
as

they
are

through
various
direction

changeover

valves

including
ON
OFF
valve
and

regulator
valves

newly
reformed
to
a

throttle

system
oil

pressure
and

op

crates
other
valves

or

finally
the
line

pressure
are
transmitted
to

the
re

quired
clutch
or
brake
servo

piston

unit
in

response
to
the

individual

running
conditions
after

receiving
sig

nals
from
the

previously
described

vacuum
diaphragm
downshift
sole

noid

governor
valve

and
or

manual

linkage

The
control
valve

assembly
consists

of
the

following
valves

Pressure

regulator
valve

2
Manual
valve

3
1st

2nd
shift
valve
4

2nd
3rd
shift

valve

S

Pressure

modifier
valve

6

Yacuum
throttle
valve

7

Throttle
back

up
valve

8
Solenoid

downshift
valve

9
Second

lock
valve

0

2nd
3rd

timing
valve

Pressure

regulator
valve

PRV

The

pressure
regulator
valve

re

ceives

valve

spring
force
force
from

plug
created

by
the
throttle

pressure

16
and
line

pressure
7
and
force

of

the

throttle

pressure
18

With
the

mutual

operations
of
those
forces
the

PRY

regulates
the
line

pressure
7
to

the

most
suitable

pressures
at
the

individual

driving
conditions

The
oil
from
the
oil

pump
is

ap

plied
to
the

ring
shaped
area

through

orifice
20
As

the
result
the
PRY
is

depressed
downward
and

moves
from

port
7

up
to
such
extent
that
the

space
to
the

subsequent
drain

port

marked
with
x
in

Figure
AT
10

opens
slightly
Thus
the
line

pressure

7
is
balanced
with
the

spring
force

AT
7
and
the
PRY
is

thereby
balanced
In

this
the

space
from
the

port
7

to
the

subsequent
converter
oil

pressure
14

circuit

has
also
been

opened
As

the

result
the

converter
is
filled
with
the

pressurized
oil
in
the
circuit
14
and

the

oil
is

further
u
d

for
the

Iubrica

tion
of
the
rear
unit
Moreover

a

part

of
the
oil
is

branched
and

used
for
the

lubrication
of
front
unit

for
the
front

and
rear
clutches

When
the

accelerator

pedal
is
de

pressed
the
throttle

pressure
16
in

creases
as

described
in
the

preceding

paragraph
oil

pressure
is

applied
to

the

plug
through
orifice
21
and
the

pressure
is

added
to
the

spring
force

As
the

result
the
PRY
is

contrarily

depressed
upward
space
to
the
drain

port
is

reduced
and
the
line

pressure

7
increases

Afl

II

Jwi
06

A

J
L
I

7

I

tf

Iij

BL

i
il
J

jti
r

x

r
1
J

I

l

I

X

6

C

l
o

ii
J

f

A

T09S

Fig
AT
10
Pressure

regulator
value

tr
r

Low
in

the

range
I
is

led
to

the
low

and
reverse
clutch
from
the

line

pressure
5

through
the
line

pressure
12
and
at
the
same
time

the
same
is
led
to
the
left
end

spring

unit

Consequently
although
the

go

vernor

pressure
increases
the
valve
is

still

depressed
toward
the

right
and

the
SFV
is

fixed
in
the
Low

posi

tion
When

kicked
down

at
the

2nd

speed
the
SDV

operates
and
the

line

pressure
13
depresse
the
FSV
to

ward
the

right

Although
the

governor

pressure
15
is

considerably
high
the

valve
is

depressed
completely
toward

the

right
and
the

FSV
is

returned
to

the
Low

position
This

operation
is

called
Kick
down

shift

2nd
3rd
shift
valve
SSV

The
SSV
is

a
transfer
vaIve
which

shifts

speed
from
2nd
to
3rd

When
the
vehicle
is

stopped
the

SSV
is

depressed
toward
the

right
by
the

spring
and
is
in

the
2nd

position
It

is

provided
however
that
the
FSV

decides
the

shifting
either

to
Low

or

2nd

When
the

vehicle
is

running
the

governor

pressure
15
is

applied
to

the

right
end
surface
and
the
SSV
is

depressed
toward
the

left

Contrarily

the

spring
force
line

pressure
3
and

throttle

pressure
19

depress
the

SSV

toward
the

right

When
the

vehicle

speed
exceeds
a

certain
level
the

governor

pressure

exceeds
the
sum
of
the

spring
force

line

pressure
and
throttle

pressure
the

valve
is

depressed
toward
the
left
and

the
line

pressure
3
is
closed
Conse

quently
the
forces

are
rapidly
un

balanced
the
force
to

depress
the
SSV

toward
the

right
reduces
and
thus
the

SSV
is

depressed
to
the
Ie
ft
end

for
a

moment

With
the
SSV

depressed
to

ward
the

left
end
the
line

pressure
3

is

connected
with
the
line

pressure

10
the

band
servo
is
released
the

front
clutch
is

engaged
and

speed
is

shifted

to
3rd

When

the
accelerator

pedal
is

de

pressed
both
the
line

pressure
3

and

the
throttle

pressure
19

are

high
and
AUTOMATIC
TRANSMISSION

therefore
the

SSV
is

retained
in

2nd
unless
ihe

governor
pressure

IS
exceeds

the
line

pressure
3
and

the

throttle

pressure
19

In

the
3rd

position
force
to

depress
the

SSV
toward
the

right
is

remained

only
on
the
throttle

pressure

16
and

the
throttle

pressure
16
is

slightly
lower
than
that

toward
the

right
which
is

applied
while

shifting

from
2nd
to
3rd

Consequently
the
SSV
is
returned

to
the

2nd

position
at
a

slightly
low

speed
side

Shifting
from
3rd
to

2nd

occurs
at

a
speed

slightly
lower

than
that
for

2nd
to
3rd

shifting

When
kicked
down
at
the
3rd

line

pressure
13
is
led
from
the
SDV

and
the
SSV
is

depressed
toward
the

right
Although
the

governor
pressure

is

considerably
high
the
valve
is

de

pressed
completely
toward
the

right

and
thus
the
SSV
is
returned
to

2nd

position
This

operation
is

called
Kick
down
shift

When
the
shift
lever
is
shifted

to

2
or
I

range
at
the

3rd

speed

the
line

pressure
3
is

drained
at

the

MNV

Consequently
the
front
clutch

operating
and
band
servo

releasing
oils

are
drained
As

the

res
lIt
the
trans

mission
is
shifted

to
the
2nd
or

low

speed
although
the

SSV
is
in

the
3rd

position

When
the

speed
is
shifted
to
the

3rd
a

one

way
orifice
24
on
the

top
of
the

SSV
relieves
oil

transmitting

velocity
from
the
line

pressure
3

to

the
line

pressure
10
and
reduces
a

shock

generated
from
the

shifting

Contrarily
when
shifted
from
3rd

to
2
or

range
and
the

speed
is

shifted
to
the
2nd

spring
of
the
orifice
24
is

depressed
the
throttle

becomes
ineffective
the

line

pressure

10
is

drained

quickly
and
thus

delay
in
the

speed
shifting
is

elimi

nated

Throttle

of
the

line

pressure
6

relieves
the
oil

transmitting
velocity

from
the

line

pressure
6
to
the

line

pressure
10
when

the
lever
is

shifted

to
the

R

range
and
relieves
drain

velocity
from
the
line

pressure
10
to

the
line

pressure
6

when

shifting

from
3rd
to

2nd
at

the
D

range
Thus
the
throttle
of
the
line

pressure
6
reduces

a
shock

generated

from
the

shifting

A

plug
in
the
SSV
left

end

readjust

the
throttle

pressure
16
which
varie

depending
on
the

engine
throttle
con

dition
to
a

throttle

pressure
19

suited
to
the

speed
change
control

Moreover
the

plug
is

a
valve
which

applies
line

pressure
13
in

lieu
of
the

throttle

pressure
to
the

SSV
and
the

FSV
when
kick

down
is

performed

When
the
throttle

pressure
16
is

applied
to
the
left
side
of
this

plug

and
the

plug
is

depressed
toward
the

right
a
slight

space
is
made
from
the

throttle

pressure
16
to

19
A
throt

tIe

pressure
19
which
is
lower

by
the

pressure
loss

equivalent
to
this

space
is

generated
the

pressure
loss
is
added
to

the

spring
force
and
thus

the

plug
is

depressed
back
from
the

right
to
the

left

When
this

pressure
19
increases

excessively
the

plug
is
further
de

pressed
toward
the
left

space
from

the

throttle

pressure
19
to
the
drain

circuit

13
increases
and
the
throttle

pressure
19
lowers
Thus
the

plug
is

balanced
and
the

throttle

pressure

19
is
reduced
in
a

certain
value
b

3
Orifice

t

checking
valve

24

15

2
2

i
I

1
c

V
Y
ii
pr

W
jt1

iff
I
W
q

I
nHH

J

L19
H
10

15

AT
9
A

T098

Fig
AT

13
2nd
3rd

shiflvalue

against
the

throttle

pressure
16

When

performing
the

kick
down

the

SOV

moves
a

high
line

pressure
is

led
to

the
circuit
19

from
the
line

pressute
circuit
13

which
had

been

drained
the

plug
is

depressed
toward

the
left

and
the
circuit

19
becomes

equal
to
the

line

pressure
13
Thus

the

kick
down
is

performed

Preasure
modifier
valve

PMV

In

comparison
with
the

operating

pressure
required
in

starting
the

vehi

ele

power

transmitting
capacity
of
the

clutch

in
other

words

required
op

erating
pressure
may
be

lower
when

the

vehicle
is
once

started
When
the

line

pressure
is
retained
in

a

high
level

up
to
a

high
vehicle

speed
a
shock

generated
from
the

shifting
increases

and
the
oil

pump
loss
also

increases
In

order
to

prevent
the
above

described

defective
occurrences
with

the

opera

lion

of
the

governor
pressure
15
the

throttle

pressure
must
be

changed
over

to

reduce
the

line

pressure
The
PMV

is
used

for
this

purpose

When
the

governor

pressure
15

which
is

applied
to

the

right
side
of

the

PMV
is

low
the
valve
is

depressed

toward

the

right
by
the

throttle

pres

sure

16

applied
to

the
area

differ

ence
of

the
value
and
the

spring
force

and

the
circuit

from
the

circuit
16
to

the

circuit
18
is

closed

However

when

the

vehicle

speed
increases
and

the

governor

pressure
15
exceeds
a

certain

level
the

governor

pressure

toward

the
left

which
is

applied
to
the

right
side

exceeds
the

spring
force
and

the

throttle

pressure
16
toward
the

right
the
valve
is

depressed
toward
the

left
and
the

throttle

pressure
is

led

from
the
circuit

16
to

the

circuit

18
This

throttle

pressure
18
is

applied
to

the

top
of
the

PRY

and

pressure
of
the
line

pressure
source
7

is

reduced

Contrarily
when
the
vehi

cle

speed
lowers
and
the

governor

pressure
15
lowers
the

force
toward

the

right
exceeds
the

governor
pres
CHASSIS

sure
the
valve
is

depressed
back
to

ward
the

right
the

throttle

pressure

18
is
drained
to

the

spring
unit

This

valve
is

switched
when
the

throttle

pressure
and
the

governor

pressure
are

high
or
when

the
throttle

pressure
is

low
and
the

governor

pres

sure
is
low

II

18
16

1JU

k
I

15

AT099

Fig
AT
14
Pressure

modifier
valve

Vacuum
throttle
valve

VTV

The

vacuum

throttle
valve
is
a

regulator
valve

which
uses

the
line

pressure
7
for
the

pressure
source

and

regulates
the

throttle

pressure
16

which

is

proportioned
to
the

force

of

the

vacuum

diaphragm
The

vacuum

diaphragm
varies

depending
on
the

engine
throttle
condition

negative

pressure
in
the

intake
line

When
the
line

pressure
7
is

ap

plied
to

the
bottom

through
the
valve

hole

and
the

valve
is

depressed

up

ward

space
from
the

line

pressure
7

to
the

throttle

pressure
16
is

closed

and
the

space
from
the

throttle

pres

sure

16
to
the

drain
circuit
17
is

about
to

open
In

this

the
throttle

pressure
16
becomes
lower

than
the

line

pressure
7

by
the

pressure

equivalent
to
the

pressure
loss

of
the

space
and
the

force
to

depress

through
the

rod
of
the

vacuum

dia

phragm
is

balanced
with
the

throttle

pressure
16

applied
upward
to

the

bottom

When

the

engine
torque
is

high
the

negative
pressure
in
the

intake

line

rises

similar
to
the

atmospheric
pres

sure
and
the

force
of

the
rod
to

depress
the
valve

increases

As
the

result
the
valve
is

depressed
down

ward
the

space
from
the
throttle

pressure
16
to

the
drain

17
re

AT

lO
duces
and
the

space
from
the

line

pressure
7
to
the

throttle

pressure

16
increases

Consequently
the

throttle

pressure

16
increases

and
the

valve
is

baI

anced

Contrarily
when

the

engine

torque
lowers
and
the

negative
pres

sure
in

the
intake
line
lowers

similar

to
vacuum
force
of

the
rod

to
de

press
the

valve
lowers
and
the

throttle

pressure

16
also

lowers

When
a

pressure
regulated
by
the
throttle

back

up
valve
described
in

the
subse

quent

paragraph
is

led

to
the
circuit

17
a

high

pressure
is

applied

through

the

space
from
the
circuit
17

to
the

throttle

pressure
16

Consequently

the
VTV
is

unbalanced
the

throttle

pressure
16
becomes

equal
to

the

back

up
ptessure
17
and
the
valve
is

locked

upward

bi

II
I

ATlOa

Fig
AT
15
Vacuum

throttle

valve

Throttle

back

up
valve
TBV

Usually
this
valve
is

depressed

downward

by
the

spring
force

and
the

circuit

17
is

drained

upward

As

soon
as
the
lever
is

shfted
either

to
2
or

range
line

pressure
is

led

from
the
circuit
4

the
line

pressure
is

applied
to
the
area
differ

ence
of
the
valve

the
valve
is

depres

sed

upward
the

space
from
the
circuit

4

to
the

circuit

17
is

timely
closed

and
with
the

space
from

the
circuit

17
to
the

upper
drain

being
about
to

open
the

back

up

pressure
17
which

is

lower
than
the

line

pressure
4

by

the

pressure
loss
due
to
the

space
from

the
circuit
4
to
the
circuit

17
is

balanced
with
the

spring
force

Further
when

speed
is

shifted
from

2nd
to

Low
at

the

range
I

line

pressure
is

led
from
the

circuit

12

and
the
line

pressure
is

applied

upward

to
the
bottom

of
the

valve

through
the

valve
hole

Consequently
the

valve
is

depressed
upward
and
locked
As
the

result

the

space
from
the

line

pressure

4
to
the

back

up
pressure
17

is

closed

completely
and

the
back

up

pressure
17
is
drained

upward

AT101

Fig
AT
16

Throttle
back

up
valve

Solenoid
downshift
valve

SDV

This
valve
is

a
transfer
valve
which

leads
the

line

pressure
7

to
13
and

transmits
the

same
to
the
FSV
and

SSV
when
a
kick
down

signal
is
re

ceived
from

the
downshift
solenoid

Usually
the
solenoid

push
rod
and

valve
are
locked

upward
by
the

spring

in

the
lower
end
and
circuit
from
the

line

pressure
4
to
the
line

pressure

13
is

opened

When

kick
down
is

performed
the

push
rod

operates
the
valve
is

depres

sed
downward
and
the
circuit

from

the
line

pressure
7

to
the
line

pres

sure

13
opens
The
line

pressure
13

opposes
the

governor
pressure
15
at

the
SSV
and
FSV
and

thus

performs

the
downshift

operation
AUTOMATIC
TRANSMISSION

AT102

Fig
AT

17
Solenoid

downshift
value

Second
lock
valve
SLV

This
valve
is
a

transfer
valve
which

assists

the
shift
valve
in
order
to

decide

the
fixed
2nd

speed
at
the
2

range

In
the

D

range
the
sum
of

the

spring
force
and

line

pressure
3

applied
upward
exceeds

the
line

pres

sure
2

which
is

applied
to
the

valve

area

difference
as
the

downward

force

As
the

result
the

valve
is

locked

upward
and
the

circuit

from
the
line

pressure
8
to
the

line

pressure
9
is

opened

Consequently
the
FSV
becomes

the
2nd

speed
condition
and
line

pressure
is

led
to
the

band
servo

engaging
circuit
9

only
when
the
line

pressure

1
is
released

to
the
line

pressure
8

In
the

2

range
the

upward
force

is

retained

only
on

the

spring
and

the

downward

line

pressure
2
exceeds

the

upward
force

As

the
result
the

valve
is

locked

downward
the
line

pressure
2
is

released

to
9

regardless
of

the

operat

ing
condition
of
the
FSV
and

the

band

servo
is

engaged

2nd
3rd

timing
valve

TMV

This

valve
is

a
transfer
valve
which

switches
the

by
pass
circuit
of
the

AT
ll
J

2

3

ATl03

Fig
A
T
18

Second
lock

ualue

orifice
22
in

the
front
clutch

pres

sure
circuit
II
in

response
to
the

vehicle

speed
and
the

throttle
con

dition
A
force
created

when
the

go

vernor

pressure
15

applies
to
the

bottom
of
the

TMV
is

used
for
the

upward
force
and
a

force
created

when

the

spring
force

and
the

throttle

pressure

apply
to
the

top
of
the

TMV

is
used
for

the
downward
force

When
the

throttle

pressure
16
is

lower
than

the

governor
pressure
15

the

upward
force

exceeds
the
down

ward
force
the
valve
is
locked

upward

and

passage
from
the
circuit
10

2nd
from
the

Top
to
the
circuit

II
is

closed

Consequently
the

line

pressure
10
is
led
to

the
front

clutch

circuit

1
I

through
the

orifice
22

and

thus
the
oil

pressure
is
trans

mitted

slowly
However
under

the

normal

shifting
the

throttle

pressure

16
has
a

pressure
exceeding
a
certain

level
and

the
downward
force
exceeds

the

upward
force
As
the
result
the

valve
is
locked
downward
the

passage

from
the
circuit

10
to
the
circuit

1
I
is

opened
and
the

orifice
22

is

disregarded

1

i
16

I
O

11

l1
1

r

X

lp

I
15

J

AT104

Fig
AT
19
2nd

3rd

timing
ualue