1977 DATSUN PICK-UP manual transmission

Automatic
Transmission

HYDRAULIC

CONTROL
SYSTEM

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

FUNCTIONS
OF

HYDRAULIC
CONTROL

UNIT
AND
VALVES

The

hydraulic
control

system
con
CONTENTS

P
RANGE
PAR

K

R

RANGE
REVERSE

N

RANGE

NEUTRAL

D1
RANGE
LOW
GEAR

D2
RANGE

2ND
GEAR

D3
RANGE
TOP
GEAR

D
RANGE
KICK

DOWN

2

RANGE
2ND
GEAR

t
RANGE
LOW
GEAR

12
RANGE
2ND

GEAR
AT
4

AT
4

AT
4

AT
5

AT
5

AT
5

AT

6

AT13

tains

an
oil

pump
for

packing
p
oil

from
the
oil

pan
through
the
oil

strainer
A

shift
control
is

provided
by

two

centrifugally
operated
hydraulic

governors
on
the

output
shaft

vacuum

control

diaphragm
and
downshift
AT14

AT16

AT18

AT

20

AT

22

AT

24

AT

26

AT

28

AT

30

AT

32

solenoid

These

parts
work
in

conjunc

tion

with
valves

in
the
valve

body

assembly
located
in

the
base
of
the

transmission
The
valves

regulate
oil

pressure
and
direct
it

to

appropriate

transmission

components

Oil

pump
I
I

Control
valve
I

Torque
converter

1

I
I

I

Manual

linkage
Front
clutch

Vacuum

diaphragm
I

Rear
clutch

I
Low
and

reverse
brake

Downshift
solenoid

I
Band
brake

Governor
valve

r
I
Lubrication

OIL
PUMP

The
oil

pump
is

the
source
of

control
medium
i

e
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

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

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

AT071

I
Housin
4

Inner

gear

2

Cover

5
Crescent

3
Ouler

gear

Fig
AT

3
Oil

pump

AT
4
MANUAL

LINKAGE

The
hand

lever
motion
the
hand

lever
is
localed
in

the
driver
s

compart

ment

mechanically
transmitted
from

lhe
remote

control

linkage
is

further

transmitted
to

the
inner

manual
lever

in
the
transmission

case
from
the

range

selector
lever
in
the

right
center

par

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
rhe
manu

al
valve

spool
of
the

conlrol
valve
thus

positioning
the

spool
opposite
rhe

appropriate
select

posilion

The

parking
rod

pin
is

held
in
rhe

groove
on
the

top
of
Ihe
inner

manual

plate
The

parking
rod

pin
operates
the

rod
at
p

range
and

operates
the

mechanical

lock

system

The

above
described
manual
shaft
is

further

equipped
with

an
inhibitor

switch
A

rotor

inside
the

inhibitor

switch

rotates
in

response
to
each

range
When
tne

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
rolor
closes
the

back

up

lamp
circuit
and
the
back

up

lamp

lights

CD

1
Manual

pia
te

2
Inhibitor

switch
ATOB7

Parking
rod

Manual
shaft

Fig
AT
4

Manual

linkage

VACUUM

DIAPHRAGM

The

vacuum

diaphragm
is

installed

on
the
left

center

portio
n
of
the

transmission

case
The

internal
con

struction
of
the

vacuum

diaphragm
is

as
follows

A
rubber

diaphragm
forms
a

parti

tion
in
the

center
The

engine
intake

manifold

negative
pressure

l
led

through
a

vacuum
tube
and

spring

force
is

applied
to
the
front
surfaceof

the
rubber

diaphragm
while

atmos

pheric

pressure
is

applied
to
the
back

surface
The
difference

between

pres

sure

applied
to
the
front
and
ba
K

I

surfaces
causes
a

vacuum
reactIOn

which
activates
the
throttle
valve
of

the
control
valve
inside
the
transrhis

sion

case

Wheri
accelerator

pedal
is

fully
de

pressed
and
the
buretor
is

fU

IIy

opened
but
th

engirie

sp
eed
is

not

suificientl
increased
the

manifold

negative
plre
sure
lowers

Le
tends

towards

atmospheric

pressure
and
the
Automatic

Transmission

vacuum
reaction
increases
since

the

flow

velocity
of
mixture
inside
the

intake
m
mifold
is
slow

Contrarily

when
the

engine
speed
increases
and

the
flow

velocity
of
the

mixture
in

creases
or

when
the
carburetor

is

closed

the
manifold

negative

pressure

increases
Le
tends

towards
vacuum

and
the

vacuum
reaction
is

reduced

Thus
a

signal
to

genera
Ie

hydraulic

pressure
P
rfe

tly
suited
to
the

engine

loading
at

trye
control
valve
is

trans

mitted
from
the
vacuum

diaphragm

and
the
most
suitable

timing
for

speed

change
and
lin
e

pressure
is
obtaine

so

that
the

most

proper
torque
capacity

is

obtained

against
the

transmitting

torque

To
inl
lkc

manifold

AT088

Fig
AT
5
Vacuum

diaphragm

DOWNSHIFT

SOLENOID

T
e

downshift
solenoid
is

of
a

magnetic
type
installed
on

the
left
re
r

portion
of
the
transmission

case
When

a
driver

requires

accelerating
power

and

dePresses
the

accelerator

pedal

down

to
the

stopper
a
kickdown

switch

19ca
ted
in
the

middle
of

the

accelerator

link
is

depressed

by
a

push

rod
he

kickdown
switch

doses
cur

rent
flows
to

the
solenoid

the
sole

noid

push
rod
is

depressed
the
down

shift
valve
of
the

control
valvc
insidc

the

transmi
ssion

case
is

depressed
nd

the

speed
is

changed
forcedly
fmm

3rd
to
2nd
within
a
cerlaill

vehi

cle

speed
limit

Note
Since
theki

kdown
switch

closes
when
the
accelerator

pedal
is

d

epr
ssed
from

7

i
t
I
S
I
6

of
tiie

whole

stroke
the
a
ccel
rator

ped
1

should

be
correctly

adjusted
so
as

arf

rd
a

omplete
stro

e
I

The

arrangement
of
the
swit

h

wries

ccording
m

eI

AT

S
c
C

r
11
I

Kickdown

h

switch

Dowri

shift
solenoid

AT089

Fig
AT
6

Downshifl80lenoid

GOVERNER

VALVE

The

primary
and

secondary

gover

nor
valves
are
installed

separately
on

the

back
of
the
oil
distributor

on
the

transmission

outp
t

sha
ft

tn

y
op

erate

al
the
same

speed
as
th
ar

iJf
tile

output
shaft
thai
is

they
operate
at

a

speed
in

proportion
10

the
vehicle

speed
The
line

press
retis

applied
to

those
valves

s
the

input
from
the

control

valve

through
the

transmission

case
rear

flange
and
oil
distributor

The

governor

pressure
in

proportion

to
the

ouiput
shaft

speed
vehicle

speed
is

led
to
the
shift
valve
ofthe

control
valve

through
the

opposite

route
of
the

output
In

this
manner

speed
change
and
line

pressure
are

controlled

Operation
of

secondary

governor
valve

T
e

secon

ary
valve

is
a

contro

valve

Y
hich
receives

line

pressure

an

cqQ
rols
the

governor

pressu
e

When
the
manual

valve
is
selected

at
D
2

or
l

range
line

pressure

is

applied
t
the
ri

g
sh

aped
area
of

this
valve
from
circuit
I

l
and
this

I

v

Jy
is

depressed
lOW
jr
tI
c

fer

Movemcnt

of
this
valvl
III
a
cr

in

positillll
doses
the
dr
uit

from

Olto

15
while

simultaneously

making
a

sr
rronl
IS
to
Iii
center

d
niin

port
and

press
re

in
tllc
ci
rJ

it

l5j
is

lowered

When

thc
vehicle
is

stopped
1
d

the

cenlrifugal
force
of
this
valve
is
zero

the
v
lve

is
balanced
At
this

poini
a

govcr
lOr

pressurc
y
hich

bal
i1
nced

with

th

spr
ng
force

occurs
on
IS

Wh
n

thc
vehicle
is

st
rted
nd

the

centrifugal

fqr
incre

ses
this
valve

movcs

slightly
10

Ihc
oUlSide
and

as

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

The
control
valve

assembly
consists

of

the

following
valves
See

Figure

AT

20

I
Pressure

regulator
valve

PRV

2

Manual
valve

MNV

3
I

st
2nd

shift
valve

FSV

4

2nd
3rd

shift
valve

SSV

5

Pressure
modifier
valve

PMV

6
Vacuum
throttle
valve

VTV

7

Throttle
back

up
valve

TBV

8
Solenoid
downshift
valve
SDV

9

Second
lock
valve
SL
V

10
2nd
3rd

timing
valve

TMV

Pressure

regulator
valve

PRV

The

pressure
regulator
valve
re

ceives
valve

spring
force
force
from

the

plug
created

by
the
throttle

pres

sure
16
and
line

pressure
7

and

force
of
the
throttle

pressure

18

With
the
interaction

of
those
forces

the
PRY

regulates
the

line

pressure
7

to
that

most
suitable
for
individual

driving
conditions

The
oil
from
the
oil

pump
is

ap

plied
to

the

ring

shaped
area

through

orifice
20
As

a
result
the
PRV
is

depressed
downward
and
moves
from

port
7

up
to
such
extent
that
the

space
to
the
next
drain

port
marked

with
X
in

Figure
AT
10

opens

slightly
Thus
the

line

pressure
7
is

balanced
with
the

spring
force
there

by
balancing
the
PRV
In
this

opera

tion
Ihe

space
from

port
7
to
the

subsequent
converter
oil

pressure
14

circuit
has
also
been

opened
As
a

result
the
converter
is
filled

with

pressurized
oil
in
circuit
14
and
this

oil
is
further
used
for
lubrication
of

the
rear
unit
Moreover

part
of
the
oil

is
branched
and
used
for
lubrication

of

the
front
unit
for
the
front
and
rear

clutches

When
Ihe
accelerator

pedal
is
de

presscd
the
throttle

pressure
16
in

creases
as
described
in
the

preceding

paragraph
oil

pressure
is

applied
to

the

plug
through
orifice
21

and
this

pressure
is

added
to
the

spring
force

As

a
result
the
PRV
is

contrarily

forced

upward
space
to

the
drain

port

is
reduced
and
Ihe

line

pressure
7

increases
Automatic

Transmission

11

AT095

Fig
AT
10
Pressure

regulator
ualue

When

the

range
is
selected
at
R

Reverse

the
line

pressure
6
is

applied
10

the

plug
in
a
manner
identi

caito
the

throttle

pressure
16
and

is

added
10
the

spring
force

Consequent

ly
the
line

pressure
7

further
in

creases

When
vehicle

speed
increases

and

the

governor
pressure
rises
the

theot

tle

pressure
18
is

applied
to
the

port

on
the

top
of
the
PRV

and

pressure
is

applied
contrarily
against
the

spring

force
As
a

result
the
line

pressure
7

decreases
Moreover
at
individual

con

ditions
the
line

pressure
7

is

equal
to
the
line

pressure
6

and
the
throttle

pressure
16
is

equal
to
18

Manual
valve
MNV

The
manual
lever

turning
motion
is

converted
to

reciprocating
motion

of

the
manual
valve

through
a

pin
and

the
MNV
is

positioned
so
that
the
line

pressure
7
is
distributed
to
the

indi

vidual
line

pressure
circuits
at
each

P

R
N

D
2
or
I

range

as

shown
below

P

range

7
4
SDV
and
TBV

5

FSV
12
TBV
and

Low

reverse
brake

R

range

7
4

same
as
above

5

same
as
above

6

PRY
and

SSV
F
C

and
band
release

N

range

D

range

7
7

None

I

Governor
valve

FSV

and
rear
clutch

2

SLY

3

SL
V

and
SSV

2

range

7
I
Same
as
above

2

SL
V
9
Band

applied

4
SDV
and
TBV

I

range

7
I
Same
as
above

4
Same

as
above

5

FSV

Moreover
1

2
3
4
5

and

6

are

always
drained
at
a

position

where
the
line

pressure
is

not
dis

tributed
from
7

u
JJX
g4Vhl

dIillillt
1
dlMIi
W
ld

IiIb
It
i
B
J

jd
l
tJj
fitMi
td

j
L@

x
x

j
j

P
R
N

17
l

AT7
AT096

Fig
AT
11

Manual
ualvp

Automatic
Transmission

d

n
ern

I

lLU
I
J

A1
094

1

Pressure

regulating
valve
PRV

2
Manual

val
MNV

31st
2nd
shift

val
fSV

4

2nd
3rd
shift

val
SSV

5

Pressure
modifier
valve
PMV
6
Vacuum
throttle
valve
VfV

7

Throttle
back

up
valve
TBV

8
Solenoid
down

shift
valve
SDV

9
Second
lock
valve
SL
V

10
2
3

timing
val
TMV

Fig
AT
20
Controloolve

AT
12

Automatic
Transmission

P

RANGE
PARK

The

operation
of
clutches
and

band

are
functionally
the
same
as
in

Neu

tral

In

parking
however
when
the

parking
pawl
meshes
in

a

gear
which
is

splined
to

the

output
shaft
the

output

shaft
is

mechanically
locked
from

rotating
Free
Lock

AT086

Fig
AT

24

Parlling
mechanum

The
oil

discharged
from
the
oil

Low
Band
ervo
On

pump
is

fed
to
each

part
in
a

similar
Gw
Clutch

Parkin

Range

atia
Il

Yer5e

r

pawl

manner
to
that
of
the
N

range
The
Fron
Rear
brakt

Operation
Release
clutch

oil

having
the
line

pressure
7
which

Park
on

has
been
introduced
into

the
manual

valve

Il
reaches
the
I

st
2nd
shift
Re
er
2
132
on
on
on

valve

CID
through
the
line

pressure

circuit

5
As
the
1st
2nd
shift
Neutral

valve
s
force
to
th

right
hand
ide
PI
L
w
2
3
on

by
the

spring
the
line

pressure
5
and

Drive
P2
Second
14S3
on
on

12
actuates
the
low
and
reverse

brake

through
the
groove
Also
Ihe
03

Top
1
000
on
on

parking
pawl
engages
with
the
outer

2
Second
1
458

teeth
of
the
oil
distributor

by
means

of
the

manual
lever
mechanically
12
Second
1458
on
on

locking
the

output
shaft

II
Low
2
453
on

AT
14

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

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