1977 DATSUN PICK-UP automatic transmission

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

2nd
3rd
timln
valve
TMV

This
valve
is
a
transfer

valve
which

switches
the

by

pass
circuit
of
the

orifice
22
in
the
front
clutch

pres

sure
circuit

II
in

response
to
vehicle

speed
and
throttle
condition
A
force

created
when
the

governor
pressure

IS
is

applied
to

the
bottom
of

the

TMV

constitutes
the

upward
force

and

a
force

created
when
the

spring

force
and
the
throttle

pressure
are

applied
to
the

top
of
the
TMV
consti

tutes
the
downward

force

When
the
throttle

pressure
16
is

lower
than
the

governor

pressure
IS
Automatic
Transmission

the

upward
force
exceeds
the
down

ward
force
the

valve
is
locked

upward

and

passage
from

circuit
l0
2nd

from
the

Top
to

circuit
II

is

closed

Consequently
the
line

pressure

10
is

led
to

the
front
clutch

circuit

II

through
the
orifice
22

and
the

oil

pressure
is
thus

transmitted

slowly

However
under
normal

shifting
the

throttle

pressure
16
has
a

pressure

exceeding
a
certain

level
and
the

downward
force
e
xceeds
the

upward

force
As

a
result
the
valve
is

locked

downward
the

passage
from

circuit

10
to
circuit

II
is

opened
and
the

orifice
22
is

bypassed

ATll
AT104

Fig
JlT
19
2nd
3rd

timing
valve

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

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

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

P

range
Park
Automatic
Transmission

L
A

r
k

8r
k

I

f

I
CID
VK

TIlro

V
lv

I
I

2
ID
Mocl

1
5
FrOl
ll

Clutch
Au

rr
tth

1
1
1

r

I

r

D

II

R
tOl
V

II

L

I
Torqu
Con
ter

0

I
ump

4

011
Coo

AM
Lubr
tlo

D
i

t
V

l

Front

o
v

n
Llrll

rt

Not
rk
t
to

Sol
n

BI

Cow
1ft
v
t

1

j
I

1111

II
I

I

il
1111
III

r
Orlflc

K

v

Throttl

Dr
ln

v

II

11
5

@
2nd
3
d

Timing

I

V
l
w
J

I
JQ

l
r
R

II

I

IKOnd
Lock

V
l

I

3J

I

t
rJ
I

q

I
rr

u

J2
3

n

l
l
J

r
A
J1

J
I

I
V
nu
l

V
l

P
21

Or
ln

LlMl

pr
r

100
10r
1

I

rlmarv

OoverrwJf
VIIfve
BIeOM
IV

OOll
nor
Y
M

Oo
or
It

Torqu
conv
ner

Throttl

Fig
A
T
25
Oil

pressu
circuit

diagram
P

range
Parh

AT
15

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