1973 DATSUN B110 lock

The
model
3N71
B

automatic
trans

mission
is
a

fully
automatic
unit
con

sisting

primarily
of
element

hydrau

lic

torque
converter
and
two

planetary

gear
sets
Two

multiple
disc

clutches
a

muItiple
disc
brake
a
band
brake
and

a

one

way
sprag
clutch

provide
the

friction
elements

required
to

obtain

the

desired
function
of
the
two

plane

tary
gear
sets

The

two

planetary
gear
sets

give

three

forward
ratios
and
one
reverse

Changing
of
the

gear
ratios
is

fully

automatic
in

relation
to

vehicle

speed

and

engine

torque
input
Vehicle

speed

and

engine
manifold
vacuum

signals

are

constantly
fed
to
the
transmission

to

provide
the

proper
gear
ratio

for

maximum

efficieq
cy
and

performance

at
all

thrqttIe
openings

The

iMiij
l

3N7I
B
has

six
selector

position
f

P
R
N
D

2
1

k
Park

position
positively
locks

the

c
ut

put
shaft
to
the
transmission

case

RY
means
of
a

locking
pawl
to

prev
nt
the
vehicle

from

rolling
either

direction

This

position
should
be
selected
when

ever
the

driver
leaves
the

vehicle

The

engine
may
be
started
in
Park

pQlition

OR
Reverse

range
enables
the

vehicle
to
be

operated
in

a
reverse

direction

N
Neutral

posItion
enables
the

engine
to
be

started
and
run
without

driving
the
vehicle
CHASSIS

DESCRIPTION

D
Drive

range
is
used
for

all

normal

driving
conditions

Drive

range
has

three

gear
ratios
frum

the

starting
ratio

to
direct
drive

2
2

range
provides
performance

for

driving
on

slippery
surfaces
2

range
can
also

be
used

for

engine

braking

2

range
can
be

selected
at

any

vehicle

speed
and

prevents
the
trans

mission
from

shifting
out

of
second

gear

I

range
can
be

selected
at

any
vehicle

speed
and
the
transmission

will

shift
to
second

gear
and

remain
in

second
until

vehide

speed
is

reduced

to

approximately
40
to
50

kmfh
25

to
31

MPH

I

range

position
prevents
the

transmission
from

shifting
out
of
low

gear
This
is

particularly
beneficial

for

maintaining
maximum

engine
braking

when
continuous

low

gear

operation
is

desirable

The

torque
converter

assembly
is

of

welded
construction
and
can
not
be

disassemble
for
service

Fluid
recommendation

Use

having

only
in

mission
automatic

transmission
fluid

DEXRON
identifications

the
3N7I

B
automatic
trans

AT
2
IA
e

l
csr
4o

J

r
s

Identification
number

Stamped
position

The

plate
attached
to

the

right

hand

side
of
transmission
case
as

shown
in

Figure
AT
I

ii

II

r

4
1
r

I

to
i

AT057

Fig
AT
1

Identification
number

Identification
of
number

arrangements

See
below

Model
code

JAPAN

AUTOMATIC

Z
TRANSMISSION
CO
LTD

I
MODEL

XOIOO

J
I
NO
2412345

Unit
number

Number

designation

2
4
2
3
4

5

L

Seriat

production

number

for
the

month

Month
of

production

X
Oct
Y
Nov
Z

Dec

Last

figure
denoting

the

year
A
D

r

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

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

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

1

range
Park

The

operation
of
clutches
and
band

are

functionally

quite
the

same
as
in

Neutral

In

parking
however

as
the

parking

pawl
meshes
in
a

gear
whkh
is

splined

to
the

output
shaft
the

output
shaft
is

mechanically
locked
from

rotating

The

oil

discharged
from
the

oil

pump
is
fed
to
each

part
in
a
similar

manner
to
that
of
the

N

range
The

oil

having
the
line

pressure
7
which

has
been

introduced
to

the
manual

valve

V
reaches
the
I
st
2nd

shift

valve

ID
through
the
line

pressure

circuit
5
As

the
1st
2nd

shift

valve
is
forced
to

the

right
hand
side

by
the

spring
the

line

pressure
5
and

I2
actuates
the
low

and
reverse

brake

through
the

groove
Also
the

parking
pawl
engages
with
the
au
tee

teeth

of
the
oil

distributor

by
the

manual
lever

mechanically
locking
the

output
shaft
CHASSIS

Free
Lock

I

l

J

1

ri
r
r0
1

1
J

r

A
T086

Fig
AT
24

Parking
mechanism

Ceo
Clutch
Low
Band
rvo
One

Parking

RanKe

atia
rever
w

y

pawl

Front
RUI

brake
Operation
Release

clutch

Park

Reverse
2
182
on
on

Neutral

01
Low
2
458
on

Drive
02
Second

1
458

03

Top
1
000
on

2
Second
1
458
on
on

12
Second
1458
on

II
Low
2
458
on

AT
14

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