1977 DATSUN PICK-UP torque

the

space
from
I

to
IS
increases

space
from
15
to
the

drain

port

simultaneously
decreases
As
a

resull

governor
pressure
of

15
increases

and
the

governor
pressure
is
balanced

with
the
sum
of

centrifugal
force
and

spring
force
The
governor

pressure

thus
changes
in

response
to
the
vehicle

speed
change
centrifugal
force

Operation
of

prlmar

governor
valve

The
valve
is

an
ON
OFF

valve

which
closes
the

governor

pressure

IS

regulated
by
the

secondary

gover

nor
valve
when
the
vehicle
reaches
the

minimum

speed
and
when
the
vehicle

speed
exceeds
a
certain

level
the

governor
opens
and
forwards

the

gov

ernor

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
Ihe

center

and
the

groove
to
15
is
closed
since

the

governor
pressure
applied
to
the

ring

shaped
area
is

higher
than
the

centrifugal
force
of
this
valve
When

the

governor
speed
exceeds
a
certain

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
circuil
5

Two
different
valves
are

employed

in

the

governor
so
that
it
will
inde

pendently
control
the

speed
at

high

and
low

speeds
That
is
within
the
low

speed

range
the

governor

pressure
is

not

generated
because
of
the

primary

valve
whereas
at
the

high
speed
range

above
the

breaking
point

governor

pressure
is

regulated
by
the

secondary

valve

The

breaking
point
is
the

point
at

which

the
function
of

one
of
the

governor
is
transferred
to

the
other

as
the

speed
changes
from
the

low

speed
to
the

high

speed
range
Automatic
Transmission

To
onlml

valve

l
Governor

pre
S1I
1I5
j

I

Q
J
J

f
1

1

CID

l

l
m

Line

pressure
t
D@

I

Primary
governor

2
Secondary

governor

3
Governor
valve

body
AT090

4

Oil
di
lributor

5

Output
sh
lft

Fig
AT
7
Cr05s
sectionallliew

of

governor

CONTROL

VALVE
ASSEMBLY
Ai09

Fig
AT

S

Output
shaft
with

oil

distributor
and

overnor

r

@

@
0

aBUlllI8

iUQlli
V

JlAU

I
Oil
distributor

2
Governor
nlve

body
A

T092

3

Primary
governor

valve

4

Secondary
governol

valve

Fig
A
T

9

Exploded
view

of
governor

Flow

cbar
of

control
valve

system

Oil
from

pump

Regulator
valve

1

I
i

j

Throttle
valve

I
I
l

Manual
valve
I

I

I

I

I

I

I

L

n
L

j
Speed
change

valve
I

I

t

t

I

I

I

I

I

I
Governor
I

I
valve

I

I

I

L
L

1
II
Auxiliary
valve

Line

pressure

j
Clutch
and
brake

The
control
valve

assembly
receives

oil
from
the

pump
and
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

outputs

More

specifically
the
oil
from
the
oil

pump
is

regulated
by
the

regulator

valve
as
line

pressure
build

up
the
line

pressure
is

fed
out
from

the
control

valve

assembly
through
various

direc

AT
6
tion

changeover
valves

including
ON

OFF
valve
and

regulator
valves
are

newly
reformed
to
a
throllle

system

oil

pressure
and

operate
other
valves

Finally
the
line

pressure
is

transmilled

to

the

required
dutch
or

brake
servo

pisJon
unit
in

response
to
the
individu

af

running
conditions
after
re

ejving

signals
from
the

va
uum

diaphragm

downshift
solenoid

governor
V
dlvc

and
or
manual

linkage

3

Jit
f
ng
valve

24

1

3

L
l

r

I
Js

I
i

ilr
t
pressure
6
when

shif
ing
from
3rd

to
2nd
at
D

range
Thus
the

throttle
of
line

pressure
6
reduces

the

shock

generated

fro
shifting

A

plug
in
the

SSV
left

end

readjust

the

throttle

piessu
e
I
6
which
varies

depending
on
the

engine
throttle
con

dition
to
a
throttle
pressure
19

suiled
to
the

sp
ed

change
control

Moreover
the

plug
is
a
valve
which

applies
line

P

esspre
13
in
lieu
of
the

throttle

pressure
to
the
SSV
and
the

FSV
when
kickdowri
is

performed

When
the
throttle

pressure
16
is

applied
to
the

left
side
of
this

plug

and
the

plug
is

epressed
toward
the

right
a

slight

space
is
formed
from
the

throttle

pressure
6
10

19
A

throt

tIepressu
19

w
1iFh
is
lower

by
the

pressure
loss

equivalent
to
this

space
is

rH

1

Pressure
Odifier
valve
PMV

I

Compared
to
the

operating

pressure

required
in

starting
th
vehicle
the

ppwer
trimsinitting
capacity
of
the

clutch
that
is

required
operating

pres

sure

may
be

lower
when
the
vehicle
is

once
started
When
the
line

pressure
is

retained
at

a

high
level

up
to

a

high

vehicle

speed
shock

gerieraled
from

the

shirring
increases
arid
the

oil

pump
loss
also
jncrdases
In
order
to

prevent
his
the
t

lrott
le

pressure
must

be
l

hanged
over

with
the

operation
of

the

governor
pressure
15
to
reduce

Ihe
line

pressure
The
PMV
is
used
for

this

purposc
Automatic

Transmission

generated
the

piessure
loss
is
adde
d
to

the

spring
force

and
the

plug
is
lhus

forced

back
from
the

right
to
the

left

When
this

pressure
19
increases
ex

cessively
the

plug
is
further

depressed

toward
the

left

space
from
the
lhrot

tle

pressure
19
to

the
drain
circuit

13

increases
and
the
throttle

press

ure

19
decreases
Thus
the

plug
is

balanced
imd
the
throttle

pressure

19
is

reduced
to
Ii
certain
value

against
the
throttle

pressure
6

Wheri

performing
kickdowri

the

SDV
moves
a

high
line

pressure
is

led

to
the
circuit

19
from
the
line

pressure
circuit

13
which
had

been

drained

the

plug
is
forced
toward
the

left

and
circuit

19
becomes

equal
to

the
line

pressure
13

I

W
15

I

A
TOgS

Fig
iT
13
2nd
3rd

shift
vallJe

I

When

the

governor
pressuie
IS

which
is

applied
to
the

right
side
of

the
PMV
is
low
the
valve
is
forced

toward

the

right
by
the
throttle

ines

sure
16

applied
to
the
area
differ

ence
of
the
value
and
the

spring
foice

and
t

he
circuit

from
circuit

16
to

circuit
18
is
closed
However
when

vehicle

speed
increases
andl
the

gaver

nor

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

throt

tle

pressure
16

toward
thc

right
the

valve
is

depressed
loward
the
lefi

and

the
throttle

pressure
is
led
from
circuit

AT

9
16
to
circuit

18
This
throttle

pressure
18
is

applied
to
the

top
of

the
PRV
and
the
force
of
the

line

pressure
source
7
is
reduced

Contra

rily
when

the
vehicle

speed
decreases

arid
the

governor

ipressure
15
de

creases
the

force
toward
the

fight

exceeds
ithe

governor
pressure
the

valve
is

forced
back
toward
the

right

and
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

tIiey
are

both
Tow
i

i
I
11

18
16

n

r

I

I

15

AT099

Fig
AT
14

Pre
ure

modifier
valve

Vacuum
thro
le
valve
VTV

The

vacuum
t
rottle
valve
is
a

regula
tor
valve

whiCh
uses
the
line

pressure
7

for
the

pressure
source

and

regulates
the

throttle

pressure
16

I

which
is

proportioned
t
the

force
of

the

vacuum

diaphragm
The
vacuum

dia

phragm
yories
depending
on
the

engine
throt
le

condition

negative

pressure
in
the

inta
e
line

When
the
line

pressure
7
is

ap

plied
to
the
bottom

through
the

valve

hole
and
the
v

a
ve
is

forced

upward

space
from
the
line

pressure
7
to
the

throttle

pressure
16
is
dosed
and

the

space
from
the
Ihrottle

pressure

16
to

the
drain
circuit
17
is
about

to

open
In

this

operation
the
throttle

pressure
16
becomes
lower
than

the

linep
s

ureY
btthe
p
e
sur

9
iv

alenl
of
the

loss
of

space
and
Ihe

force

depressing
tlie
rod
if
the

vaeuum

diaphragm
is

balanced
wit

Ii
thethrot

tie

pressure
16
a

pplied
upward
tOlthe

bottom

When
the

erigine

torque
is

high
Ihe

negative
pressure
in
the
intake
iirie

rises

tending
ioward

atmospheric

pressure
and
the
force
of
the
rod
to

depress
the
valve
increases
As
a
result

the
valve
is

depressed
downward
the

space
from
the
throttle

pressure
16

to

the
drain

17
decreases

and
the

space
from
the
line

pressure
7
to

Ihe

throttle

pressure
16
increases

Consequently
the
throttle

pressure

16
increases

and
the

valve
is

bal

anced

Contrarily
when
the

engine

torque
lowers
and
the

negative
pr

sure
in

the
intake
line

lowers

tending

toward
vacuum
the
force
of
the

rod

depressing
the
valve
decreases

and
the

throttle

pressure
16
also
decreases

When

pressure
regulated

by
the
throt

tle

back
p
valve
described
in
the

subsequent
paragraph
is
led
to
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
pressure
17
and
the

valve
is

locked

upward

I

16

III
AT100

Fig
AT
15

Vacuum

throttle
valIN

Throttle

back

up
valve

TBY

Usually
this

valve
is

depressed

downward

by
the

spring
force

and

circuit

17
is

drained

upward

As

soon
as
the
lever
is

shifted
either

to
2

or
I

range
line

pressure
is

led
from

circuit
4

the
line

pressure
is

applied
to
the
area
difference

of
the

valve
the

valve
is
forced

upward
the

space
from

circuit
4
to
circuit

17
is

closed

and
with
the

space
from
circuit
Automatic
Transmission

17
to
Ihe

upper
drain
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

circuit
4
to

circuit

17
is
balanced

with

the

spring
force

Further
when

gear
is

shifted
from

2nd

to
Low

at
the

range
I
line

pressure
is

led
from
circuit

12
and

the
line

pressure
is

applied

pward
to

the
bottom
of
the

valve

through
the

valve
hole

Consequently
the
valve
is

forced

upward
and
locked
As
a

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
lJ
Jlve

Solenoid

downshift
valve

SDY

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
kickdown

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
the
circuit
from

line

pressure
4
to
line

pressure
13
is

opened

When
kickdown
is

performed
the

push
rod

operates
Ihe
valve
is
de

pressed
downward
and
the

circuit

from
line

pressure
7
to

line

pressure

13

opens
Line

pressure
13

opposes

the

governor
pressure
15
at

Ihe
SSV

and
FSV
thus

accomplishing
the

downshift

operation

AT
10
r

AT102

Fig
AT
17

Solenoid

dow
hift
valve

Second

lock

valve
SLY

This
valve
is
a
transfer

valve
which

assists
the
shift

valve
in

determining

the
fixed

2nd

speed
at

the
2

range

In

the
D

range
the

sum
of
the

spring
force

and
line

pressure
3

APplied

upward
xce
ds
the

linepres

sure
2
which
is

applied
to

the
valve

area
difference

as
a
downward
force

As
a
result

the
valve
is

locked

upward

and
the
circuit
from
line

pressure
8

to
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
line

pressure

1
is
released

to
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
a
result
Ihe
valve
is

locked

downward
line

pressure
2
is

released

to

9

regardless
of
the

operating

condition
of
the
FSV
and
the

band

servo

is

engaged

J

2

8

ATl03

3

Fig
AT
18
Second
lock
lJ
Jlve

HYDRAULIC
SYSTEM

AND

MECHANICAL

OPERATION

The

operating
system
of
oil

pres

sure
in

each

range
is

described
below

The
oil

pressure
in
each
circuit

shown
in

the
illustration
is
classified
as

follows

according
to
the

function

fhe
numeraJs
show

the
circuit

num

bers

Pressure
source
of
the
line
7

Operating
Iinc

prcssure

for
friction
elements

123456
8910
1112

Auxiliary
line

pressurc
13

Throttle

system
pressure

16
17
18

19

Others
14
15

Oil

pump
discharge
hole
7

Cd

Torque
converter

pressure
14

Rear
iutch

prc
surc
1

FTOOI
c1
tL
h

prc
ur

It

J
1
011
pump
Sllctlon
hole

M

IIJ1iIII
Automatic
Transmission

Fig
AT
21

Identification
of
oil
channels

in
oil

pump
AT105
Oil

pump
suction
hole

ATl06

Fig
AT

22

Identification
of
oil
channels
in
case

front
face

I
o

Oil

pump
dischar
hole
7

I9JM

c

Torque
converter

f
Os
I
1L

0
ervo
Ie
ease

pressure
14

0
pressure
10

Rear
clutch

Servo
t

ightening

ho
L

pressure
l
0
1

pressure
9
lJ
L

I
c

I

Front
clutch
IT

0

LIO
reverse
brake

pressure
12

U

r
FT

II
pressure
11

rrOil
pump
suction
hol

J

C
Jf
JC
O
Governor

pressure
15

Governor

feed

pressure
l

An07

Fig
AT
23

Identification
of
oil
channels

in
case

face

AT
13

R
RANGE
REVERSE

In
R

range
the

front
clutch
and

the
low
and
reverse
brake
are

applied

The

power
flow
is

through
the

input

shaft
front
clutch
and

connecting

shell
to
the

sun

gear
Clockwise
rota

tion
of
the
sun

gear
causes
counter

clockwise
rotation
of
the

rear

planeta

ry
gears
With
the

connecting
drum

held

stationary
by
the
low
and

reverse

brake
the
rear

planetary
gears
rotate

the
rear
internal

gear
and
drive
the

flange
counterclockwise
The

rear

drive

flange
splined
to
the

output
shaft

rotates
the

output
shaft
counterclock

wise
at
a

reduced

speed
with
an

increase
in

torque
for
reverse

gear
Automatic
Transmission

R

Fig
AT

26
Power

tranamis
ion

during
R

range

m
i

1

A
TOBS

Fig
A
T
21

Optrationof
each
mechanism

during
R

range

When
the
manual
valve

V
is

posi

Clutch
Low

Band
servo
One

tioned
at

R

range
the
oil

having
the
Gear

Partina

Ranae
re
ne

way

line

pressure
7
is

directed
to
line
ralio

Front
Rear

brake
Openlion
Relulie

clutch
plwl

pressure
circuits
5

and
6
The

pressure
in
the
circuit
5
actuates
the
Park
on
on

low
and
reverse

brake
after

being
Ruene
2
182
on
on
on

introduced

into
line

pressure
circuit

Neutral

12

through
the
I

st
2nd
shift
valve

ID
The

pressure
in

the
circuit

op
DI
Low
2
458
on
on

erates
the
release
side
of
the
band

servo
and
the
front
c1u
tch
after

being
Driowe
D2
Second
1
458
on
on

led
to
line

pressure
circuit
0
D3

Top
1
000
on
on
on

through
the
2nd
3rd
shift
valve

@

2
Second
1
458

The
throttle

pressure
I
6
and
the
line
on
on

pressure
6
which

vary
with
the

12
Second
S8
on
on

degree
of
accelerator

pedal
depression

II
Low
2
458

both
act
the

pressure
regulator
on

on

on

valve

CD
and

press

against
its
valve

CD

increasing
line

pressure
7
In
Rn

range
the

governor

pressure
is
absent

making
all

such
valves
as
the
1st
2nd

shift
valve

ID
lnd
3rd
shift

valvc

@
and

pressurc
modifier
valve

inoperative

AT16

R
range
Reverse

Torq
Con

Oil
Cool
r

A
r

Lubt

lcetlon

0

II
iL
Vel

o

Front

or
ln

l

n

jL
r

x

Q

A
uletor

Val

NIJte
kld
Automatic
Transmission

@
2nd
3n
l

Timl
lil

1i
II

r

U

nu

r
l3
ni

II

15
15
Front

Cll
ltc
Il
Low

a
Aev

Br
k

B
k

II
I

LJ

2f
ID
p
Mc
e
lf
v

If
I
I

CID
VEL
1

Thrc

r

V
I

I

11
1

IU

T
R

Clutch

f

r

Ir
l
II

Orlflc

Check

Velve

22

n
@lnd
3rdShlft

v

D
h
III

r
r
I

I

111

L

Ll
p
O
nOl
f
t

p
r

Goy
norpreat
l

Torque
Ilrfl

r

Throttl

D
ln

v

5

1

O
eln

rmrp

Throttl
p
a
nor
v
11

J

I

t

Q
V

1ve

Fig
A
T
28
Oil

preBBure
circuit

diagram
R

range
Reverie

AT
17

N
RANGE

NEUTRAL

In

N

range
none
of

the
clutches

and
band
are

applied
thus
no

power
is

transmitted
to

the

output
shaft

The

pressure
of
oil

discharged
from

the
oil

pump
is

regulated
by
the

pressure
regulator
valve

Dto
maintain

the
line

pressure
7

and
the
oil
is

led

to
the
manual
valve

@
vacuum
throt

tie
valve

@
and
solenoid
down
shift

valve

@
The
oil
is
further
introduced

into

the

torque
converter
at
its

op

erating

pressure
14
and
a

portion
of

this
oil

is
distributed
to
each

part
as

the
front
lubricant
The
oil
which
has

been

discharged
from
the

torque
con

verter
is

also
distributed
to
eacn

part

as
the

rear
lubricant

As
the
oil

pump
rotates
at
the
same

speed
as
the

engine
the
oil

pump

discharge
increases
with

engine

speed

But
the

surplus
oil
is
returned
to
the

oil

pan
by
the

pressure
regula
tor
valve

D
Automatic
Transmission

Geu
Clutch
Low
4

Band
crvo
One

Pultin

R

atio
WI

pawl

Front
Rear

brake
Operation
Release

clutch

Park
on
on

Reverse
2
182
on
on
on

Neutral

Dt
Low
2
458
on

on

Drive
D2
Second
1
458
on
on

m

Top
1
000
on
on

on
on

2
Second
1
458
on

on

12
Sec
ond
1
458
on
on

II
Low
2
458
on
on

AT
la

Automatic
Transmission

R
RANGE
REVERSE

R

In
R

range
the

front
dutch
and

the
low
and

reverse
brake
are

applied

The

power
flow
is

through
the

input

shaft
front
clutch
and

connecting

shell
to

the
sun

gear
Clockwise
rota

tion

of
the

sun

gear
causes
counter

clockwise
rotation
of
the
rear

planeta

ry

gears
With
the

connecting
drum

held

Slationary
by
the
low
and
reverse

brake
the
rear

planetary
gears
rotate

the
rear
internal

gear
and
drive
the

flange
counterclockwise
The
rear

drive

flange
splined
to
the

output
shaft

rotates
the

output
shaft
counterclock

wise
at

a
reduced

speed
with
an

increase
in

torque
for
reverse

gear

f

When
Ihe
manual
valve

CV
is

posi

tioned
at
R

range
Ihe
oil

having
Ihe

line

pressure
7
is

directed
to

line

pressure
circuits
5
and

6
The

pressure
in

the
circuit
5
actuates
the

low
and
reverse
brake
after

being

introduced
into
line

pressure
circuit

12

through
the
I
st

2nd
shift
valve

@
The

pressure
in
Ihe

circuit

op

erates
the
release
side
of
the
band

servo
and

the
front
clutch
after

being

led
to

line

pressure
circuit

10

through
the
2nd
3rd
shift
valve

@

The
throtlle

pressure
16
and
the
line

pressure
6

which

vary
with
the

degree
of
acceJerator

pedal
depression

both
act

on
the

prcssure
regulator

valve

CD
and

press

against
its
valve

CD

increasing
line

pressure
7
In
R

range
the

governor

pressure
is
absent

making
all
slldl

valves
as
the
J
SI

2nd

shift
valve

@
2nd
3rd
shift
valvc

@
and

pressure
modifier
valve

j

inoperative
C

Fig
AT

26
Power

transmi
ion

during
R

range

A
TOS5

Fig
AT
27

Operation
attach
mechanism

during
R

range

G
Clutch
Low
A

Band
servo
One

Parkin

Ran
no
wa

plwl
ratio

Front
Rear

brake

Operllioo
Rdr
ue

clutch

k
on
on

Revctte
1
181
on
on
on

Neutnl

DI
Low
1
418
on
on

Driw
D2
Second
1
458
on
on

DJ

Top
1
000
on
on
on
on

2
Second
1
458
on
on

12
Second
1
458
on
on

I

II
Low
2
458
on
on

AT
16