1973 DATSUN B110 manual transmission

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

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

R

range
Reverse

In
R

range
the

front
clutch

and

low
and

reverse
brake

are

applied
The

power
flow
is

through
the

input
shaft

front

clutch

connecting
sheU
and
to

the

sun

gear
Clockwise
rotatiun
of
the

sun

gear
causes

counterclockwise

rotation

of
the
rear

planetary
gears

With
the

connecting
drum
held
sta

tionary
by
the
low

and
reverse
brake

the
rear

planetary

gears
rotate
the
rear

internal

gear
and

drive

flange
counter

clockwise
The
rear
drive

flange

splined
to
the

output
shaft
rotates

the

output
shaft
counterclockwise
at
a

reduced

speed
with
an
increase
in

torque
for
reverse

gear

J

When
the

manual
valve

V
is

posi

tioned

at
R

range
the
oil

having
the

line

pressure
7
is

directed
to
the
line

pressure
circuits

5
and
6
The

pressure
in

the
circuit

ID
actuates

the

low

and
reverse
brake
after

being

introduced
into

the
line

pressure
cir

cuit

I2

through
the
lst

2nd
shift

valve

ID
The

pressure
in

the

circuit

operates
the
release
side
ofband

servo

and
the
front
clutch
after

being
led

to

the
line

pressure
circuit

10

through

the
2nd

3rd
shift
valve

@
The

throttle

pressure
16
and
the

line

pressure
6
which

vary
with
the

degree
of
the

depression
of
accelerator

pedal
both
act
on

the

pressure
regula

tor
valve

CD
and

press
its
valve

CD

increasing
the
line

pressure
7
In
R

range
the

governor

pressure
is
absent

making
all
sllch
valves

inoperative
as

the
lst
2nd

shift

valve

@

2nd
3rd
shift
valve
and

pressure

modifier
valve

@
CHASSIS

R

C

Fig
AT
26
Power
transmission

during
R

range

lI

a

Go

I
w
L

AT085

Fig
AT

27

Operation
of
each
mechani6m

duirng
OR

range

Clutch
low
Band
servo
One

Parking

Ran
Gear

ratio
reverse

way

pawl

Front
Rear

brake
Operation
Release

clutch

Park
on
on

Reverse
2
182
on
on
on

Neutral

01
low
2
458
nn
on

Drive
D2
Second
458
nn
on

OJ

Top
1
000
on
on

2
Second
458
nn

t2
Second
458
on

tt
low
2
458
on
on

AT

16

CHASSIS

D

range
Low

gear

The

low

gear
in
D

range
is

somewhat
different
from
that
in

II

range

The
rear
clutch

is

applied
as
in

range
but
the
une

way
duldl
is

holding
the

connecling
drum
The

power
flow
is
the
same

as
in

11

range
That
is
the

power
flow
takes

place
through
Ihe

input
shaft

and
into

the
rear
clutch

The

input
shaft
is

splined
to
the

rear
clutch
drum
and

drives
it

Rotation
of
the

rear
clutch

dri
es

the
rear
clutch

hub
and

from

internal

gear

The
front
inlernal

gear
rotates
the

front

planetary
gears
clockwise
to

cause
the
sun

gear
to
rotate
counter

clockwise

Counterclockwise
rotation

of
the
sun

gear
turns
the
rear

planetary

gears
clockwise
With

the

Tear

plane

tary
carrier
held

stationary
by
the

one

way
clutch
the

clockwise
rotation

of
the

rear

planetary

gears
rotates
the

rear
internal

gear
and
drives

flange

clockwise

The
internal
drive

flange
is

splined
to
the

output
shaft

and
rotates

the

output
shaft
clockwise

When
the
manual
valve
is

posi

tioned
at
D
the
line

pressure
7

introduced
into
the
manual
valve
is
led

to
the
line

pressure
circuits
I
2

and
3

The

pressure
in
the
circuit
I

actuates
the

rear
clutch
and
the

gover

nor
and
at
the
same

time

operates
the

lst

2no
shift
valve

ID
to

change
the

speed
The
circuit
2
leads
to
the

second
lock
valve

@
The
circuit
3

actuales
the
2nd
3rd

shift
valve

0

for
the
2nd

3rd

speed
change
and

at
the

same
time

locks
the
second

lock
valve

@

The
throllIe

pressure
16

which

changes
with
the

degree
of
accelerator

pedal
depression
presses
the

pressure

regulator
valve

CD
and
increases
the

line

pressure
7
When

Ihe

speed
of

vehicle
has
increased
the

governor

pressure
J
5

inlroduced
from
the
line

pressure
circuit

ll
actuates

the

lst
2nd
shift

valve
ID
2nd
3rd

shift
valve

@
and

pressure
modifier

valve

@
When
the

governor
pressure

is

high
the

pressure
modifier
valve

CID

acts
in
such

a
direction
as
to

compress
C

AT080

Fig
A
T
30
Power
transmission

during
V
range

ATOP1
dmifi

Fig
AT

3
Operation

of
each
mechanism

during
VI

range

G
Clutch
Low

Band
rVo
One

Parking

Ro
reverse

woy

pawl
ratio

Front
Rear

brake
Operation
Release

clutch

Park
on

on

Reverse
2
182
on
on

on

Neutral

01
low
14

8
on
on

Drive
01
Second

1
458
on

on

03

Top
1
000
on
on
on
on

1
Second
1
458
on
on

tl
Second
1
458
on
on

1

II
low
2
458
on
on

rhe

spring
and
the

throttle

pressure
is

led

10
the
throllIe

pressure
18

This

pressure
acts

againsr
the
force
of

spring
of
the

pressure

regulator
valve

CD
and
also

against
the

Ihrollle

pres

sure

16
thus

lowering
the
line

pres

sure
7

The

governor
pressure
also

increases

with

the

speed
of
vehicle

exerting
a

pressure
on
one
side
of

the
1st

2nd

shift

valve
and

counteracts
the

throt
lie

p
ssure
19
line

pressure
I
and

the

spring
which
are

exerting
against

the

governor

pressure
Therefore

when

the

governor
pressure
exceeds

this

pressure
the

speed
is

shifted
from

Ihe
I
Sl

gear
10
the

2nd

gear
The

further
the

acceleraror

pedal
is
de

pressed
the

higher
becomes
the

throt

tle

pressure
19

increasing
the

gover

nor

pressure
and

shifting
the

speed

change

point
to
the

higher
side

AT
20

AUTOMATIC
TRANSMISSION

D

range
2nd

gear

Q
FrO
ll

Cluteh
Low

to
R

B
e

8
eke

Torque

Con
ert

14

Throttle

Beck

up

V
l

iftV
I
a
Q

T
COU

P

R
V

A
Lubfkatlon

11

Drain

14

V
I

l
CID
V

Thro

Valli
7

If
SOle

Wo

Front

Lubrlc
at

n
Orific

Check

V

I
OralnValw

Tt
oW

Q
aln

V

l
S
P

Modit
V

2

S

13

j
P

RIGulato
Vel
@2nd
3
dShIH

V

I

13

c

33J

2nd

ShlftV
I
e

s

Manual

V

I

n

NOla
M
ked
X
r
Drein
r
D

I
U

jeeo
v
Primarv

Gov
no
Valva
Goyarno

Val
Li
p
su

aIGo
no
IMod

pr
surel

Gov
nO

pr
sur

TO

Qu
con

pr

Th
on

p

Fig
A
T
35
Oil

pressure
circuit

diagram
D2

range
2nd

gear

AT
23

CHASSIS

2

range
2nd

gear

In
2

range
the

gear
ratio
is
locked

to
the
2nd

forward

speed
In
this
case

the
rear

clutch
is

applied
and
the
band

brake
holds
the

front
clutch
drum

connecting
shell

and
sun

gear
from

rotating

The

power
flow

takes

place
through

the

input
shaft
into
the

rear
clutch
and

the

front
internal

gear
With
the

sun

gear
held

stationary
the
front

plane

lacy
gears
rotate
around
the

sun

gear

carrying
the

front

planet
carrier
with

them
The
front

planet
carrier

being

splined
to
the

output
shaft

causes

clockwise

rotation
of
the

output
shaft

at
a
reduced

speed
compared
with
the

speed
of
the

input
shaft
with

an

increase
in

torque
As
the
low
and

reverse
brake
is
not

applied
the
clock

wise
mlation
of
the

output
shaft

causes
clockwise
rotation
of
rear
inter

nal

gear
and
the
rear

planet
carrier

also

rotates
around
the

sun

gear
in
a

clockwise
direction
The
one

way

c1urch
will
act
to

allow
the
clockwise

rotation
of

connecting
drum

When
the

manual
valve

CV
is

posi

tioned
at
2
the
line

pressure
7
is

introduced
into
the
line

pressure
cir

cuits
I
2
and
4
The
line

pressure

I
is
led
to
the

governur
rear
dutch

and
Ist
2nd

shift
valve

ID
as
in
the

case
of
D

range
The
line

pressure

2
locks
the
second
lock
valve

@
and

is
led
to
the

tightening
side

of
the

band
servo

The
2nd

gear
is

therefore
fixed

regardless
of
the
car

speed
When

DJ
range
3rd

gear
is
shifted
to

2

range
the
line

pressure
4
enters
the

throttle
back

up
valve
IJ
and

produces

a

high
pressure
in

the
circuit
17

increasing
the
throttle

pressure
16

The

line

pressure
7
is

therefore

increases
and

quickly
tightens
the

band

Note

DJ
range
3rd

gear
to
2

range

If

DJ
range
3rd

gear
is

shifted
to
2

range
during

operation
the
manual

valve

CV

is
also
shifted
to
2

position
Fig
A

T
40
Powu
transmission

during
2
range

f
IY

9
3

AT079

Fig
A
T
41

Operation
of
each
mechanism

during
2

range

Gear
Clutch
low
Band
servo
On

Parking

Range

ratio
w

pawl

Front
Rear

brake
Operation
Relea
se

clutch

Park
on
on

Reverse
2
182
on
on
on

Neutral

I
t
Low
2
4S8
on
on

Drive
1
2
Second
1
458
on
on

1

Top
t
OOO
on
on
on
on

2
Second
1
458
on
on

12
Second
1
458
on
on

t

tt
Low
2
458
on
on

causing
the
line

pressure
circuit

3
to
be

drained
Therefore

the
line

pressure
circuit
10

which
is

situated
at
the

release

side

of
the
front

clutch
and

senro

is
also
drained

through

the
2nd
3rd
shift

valve

@

forcing
the

speed
to
decrease
from
3rd

gear
to
2nd

gear

In
this
case

the

speed

change

quickly
takes

place
because
the

line

pressure
7
and
other

pres

sure
are

heightened
by
the

action
of
the
line

pressure
4

in
the
same
manner
as
de

scribed
under
2

range

AT
28