1977 DATSUN PICK-UP brake

Malnshaft

assembly

Same
as
for
the
F4W7IB

Countershaft

assembly

Same
as
for

the
F4W71
B

Main
drive

gear
assembly

Procedures

are
the

same
as
for
the

F4W7IB
trans
i

n

except
as

follows

I

Insert
countershaft
and
mainshaft

into

adapter

plate
and

place
adapter

plate
in

a
vise
with

setting
plate
Manual
Transmission

Synchro

ring

8andbrake

Circlip

Anchor

block

TM449

Fig
MT
70

Imtalling
overdrive

gear
assembly

Install

snap
ring
spacer
needle

roller

bearing
reverse
idler

gear
spacer

and

snap
ring

h
I

L

TM4S1

Fig
MT
71
R
lJerse
idler

gear

MT

20
2

Assemble
OD
reverse

synchro

nizer

assembly
OD

gear
bushing

needle

bearing
OD

gear
assembly

sreel
ball
and

thrust
washer

on
main

shaft
rear
side
Before

installing
steel

ball

apply
grease
to

it

3

Install
new
mainshaft

nut
and

tighten
it

temporarily

4

Install
counter
reverse

gear

counter
5
th

gear

bearing
and
new

countershaft
nut

Tighten
nut
tem

porarily

5

Tighten
mainshafl
and
counter

shaft
nuts
and
stake
nuts
at

groove
in

shafts
with

a

punch
Tightening

proce

dures

for
mainshaft
nut
are
the
same

as
those
for
the
F4W7IB

Shift
forks
and
fork

rods

assembly

Same

as
for

the
F4W71
B

u
TRANSMISSION

ASSEMBLY

Same
as
for

the
F4W71
B

INSTALLATION

Same

as
for

the
F4W71
B

The
model
3N7l
B
automatic

trans

mission
is

a

fully
automatic

unit
con

sisting
primarily
of
3
element

hydrau

lic

torque
converter
and

two

planetary

gear
sets
Two

multiple
disc
clutches
a

multiple
disc
brake
a
band
brake
and

a
one

way

sprag
clutch

provide
the

friction
elements

required
to
obtain

the
desir
d
function
of
lhe
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
V

chide

speed

and

engine
manifold
vacuum

signals

are

constantly
fed
to
the

transmission

to

provide
the

proper
gear
ralio
for

maximum

efficiency
and

performance

at
all
throttle

openings

The
model
3N71
B
has
six

selector

1

9sition
LP
R

N
D
2
1

I

Park

position
positively
locks

the

output
shaft
to

the
transmission

case

by
means
of
a

locking

pawl
to

prevent
the
vehicle
from

rolling
in

either
direction

This

position
should
be

selected

whenever
the
driver
leaves
Ihe
vehicle

Thc

engine

may
be
slarted
in
Park

position

R
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

0
Drive

range
is
used

for
all

normal

driving
conditions

Drive

range
has
three

gear
ratios

from
the

starting
ratio

to
direct
drive
Automatic
Transmission

DESCRIPTION

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
I

range
can
be

selected
at

any
vehicle

speed
and
the
transmission

will
shift
to

second

gear
and
remain
in

second
until
v

hicle

speed
is
reduced

10

approximately
40
to
50

kmfh
25

to
30
MPH

I

range
position
prevents
the

transmission
from

shifting
out
of
low

gear
This
is

particularly
beneficial
for

maintaining
maximum

engin
braking

when

continuous
low

gear
operation
is

desirable

The

torque
converter

assembly
is
of

welded

construction
and
can

nOlbe

disassembled

for
service

FLUID
RECOMMENDATION

Use
automatic
transmission

fluid

having
DEXRON
identifications

only
in
the
3N71
B

automatic
transmis

sion

IDENTIFICATioN
NUMBER

Stamped

position

The

plate
is

attached
to
the

right

hand

side
of
transmission
case

as

shown
io

Figure
AT

I

AT
2
AT344

Fig
AT
I

Identification
number

Identification

of
number

Arrangements

See
below

Model
code

JAPAN

AUTOMATIC

0J
TRANSMISSION
CO
LTD

I
MODEL
X2402

I

J
I
NO

4912345

I

Unit
number

Number

designation

4
9

I

234
5

L

Serial

production

number
for

the
month

Month
of

production

X

Oct
Y

Nov
Z
Dec

last

figure
denoting

the

year
A
D

Automatic
Transmission

o
J

II

IIlI

r
I
r

A

T288

I
Transmission
ca
e

2
Oil

pump

3
Front
clutch

4
Band
brake

5

Rear
clutch

6
Front

planetary
gear

7
Rear

planetary
gear

8
One

way
clutch

9
Low

Rever5e
brake

10
Oil
distributor
II

Governor

12

Output
shaft

13
Rear
extension

14
Oil

pan

IS
Control
valve

16

Input
Jlihafl

17

Torque
converter

t
8
Converter

housing

19
Drive

plate
Tightening

torque
T
of

bolts
and
nuts

kg
m

ft
lb

@
T

4105
29

10
36

@
T

141016
10110116

@
T
4
5

to
5
5
33
1040

@
T

0
6100

8
4
106

@
T
0
5
to
0
7
4
10
5

T

2
0102
5
14
10
18

@
T
1
3
10
1

8
9
10
13

T

0

55100
75
4
105

CD
T
0
25
10
0

35
2
to
3

Fig
AT
2
Cross
sectional
view
of
3N71B
automatic
transmission

AT3

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

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

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