1973 DATSUN B110 low oil pressure

AUTOMATIC
TRANSMISSION

D

range

Top
gear

Low
r

Fl

B
e

B
e

B

14

TIC
Uil

Pr

1
v

Fl

Lubfk
tlon

O
ein
14

I

Velv8

l

Front

Lub
icet
Orlfiu

Check

V

I
8
6

13

@
2nd
3rd
Shifl

Velv

13

I
O
inV

Throttle

O
in

Ve

l

1

22

21

3
lit
2nd
Shift
Ve

5

M

V

I

5

n

NOle
M

ked
O

ein

Linep
s
Go
no
f
d
P

G
ernorp

Torqu
con
tt

p
secondary

G
norv
Ime

v

Governor
v

Th
Olt

p

Fig
A
T
38
Oil

pressure
circuit

diagram
D3

range
Top

gear

AT
25

AUTOMATIC
TRANSMISSION

2

range
2nd

gear

To

queCo
Low
a

R

8

ka

8
ke

Oownltlift

Solenoid

14

12

@
VK

Throt

V

I
7
Throttl

Sack

up

V
lv
@SOl

o
if
V
I

Front

Lubrk
n

Orltlc

Ch
k

V

l
Dr
n
V

1

ThroW

Drain

V
Ye
Pt

Mod
fier
V
I

IS

8Rt

@2
3rdTimi
Sl

It

V

12

3
ht
2nd

Sf
ll

5

Secor
d
Lock
V
I

3
I

@
M
nu
l

V

I

5
I1Jl
ill
Pr
ur

R
vulatO
V
I

Note
M

keel
r
D

in

a

P

imary

Go
no
V
h
Line

pr

IGo
no

teed
p
luure

Go

no
p

E2I
B
Ii
iiiIJ
To

c
U
con

t
p

Th
oUl

prn
SecOnda

y

00
0

V
lv

Fig
AT
42
Oil

pressure
circuit

diagram
2

range
2nd

gear

AT
29

CHASSIS

1

range
Low

gear

When

starting
in
I

range
the

driving
gear
is
locked
to
the
low

gear

ratIO

In
1

range
the

reaT
dutch

is

applied
and
the
low
and
reverse
brake

holds
the

connecting
drum
and

rear

planet
carrier
from

rotating
The

power
flow
takes

place
through
the

input
shaft
and
into
the
rear
dutch

Rotation

of
the
rear
clutch
drives
the

rear
clutch
hub

and
front
internal

gear

The
front
internal

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
gear

clockwise

The
rear

planet
carrier

splined
to

the

connecting
drum
is
held
from

rotating
by
the
low
and

reverse
brake

The
clockwise
rotation
of
the
rear

planetary
gears
therefore
rotates
the

rear
internal

gear
and

internal
drive

tlange
The

internal
drive

tlange
is

splined
to
the

output
shaft
and
rotates

the

output
shaft
clockwise
However

the

output
shaft
rotates
at
a

lower

speed
compared
with
that
of
the

input

shaft
This
is

caused

by
the
fact
that

the
front

planet
carrier
rotates
at
the

same

speed
as

the

output
shaft
in
the

same
direction
since
the
carrier
is

splined
to

the

output
shaft
The

front

internal

gear
and

planetary

gear
as

sembly
are

rotating
in
the

same
direc

tion
but
the

planet
carrier
is

rotating

at

a

speed
slower
than
the

ring
gear
So

the

gear
ratio

of
this

speed
range
is
a

combination
of
the
ratios

provided
by

the
front
and

rear

planetary
gear
a

semblies

When

the
manual
valve

CV
is

posi

tioned
at
I
the
line

pressure
7
is

applied
into
the

line

pressure
circuits

I
4
and
5
The

oil

pressure
in
5

actuates
the

low
and

reverse
brake

after

being
introduced
into

the
circuit

12

through
the

lst
2nd
shift
valve

@
and

the
line

pressure
I

acts
on
i

C

AT076

Fig
A
T

43
Power
transmission

during
11

range

A

Ton

Fig
A

T
44

Operation
of
each
mechanism

during
11
range

Clutch
Low

Band
rvo
On

Parking

Range
Gm

ratio
reverse
w

pawl

Front

Rear

brake
Operation
Release

clutch

Park
on
on

Reverse
2
182
on
on
on

Neutral

DI
low
2
458
on
on

Drive
D2
Second
1
458
on
on

D

Top
1
000
on
on
on
on

2
Second
1
458
on
on

12
Second
1
458
on
on

I

Low
2
458
on
on

the

rear
clutch
and

governor
The
line

pressure
4
acts
in

the
same
manner
as

in
2

range

Similar
10
that
of
the
D

range

the
line

pressure
increases
with
the

degree
of

depressiun
of
the
accelerator

pedal
and
the
line

pressure
decreases

with
the
increase
of

car

speed
The
governor
pressure
IS
which
acts
on

the
Ist
2nd

shift
valve
does

not

increase
until

it
overcomes
the
com

bined

force
of
the

line

pressure
12

and
the

spring

causing
nu
I

st
2nd

speed

change

AT
3D

AUTOMATIC
TRANSMISSION

1

range
Low

gear

Lo
Rev

B
k

Brat

Oownthift

SolenoOCl

14

T
COUP

A
uu
e

IV
hl

I

R
L
ub
c
tlon

Dr
n

It

Val
9
10
v

nHOI

V

l
in

jl

8
Sale
d

QI

Cow
ilt
V

D
nV
Front

Lubtlc
t
Oritice

ChotCk

Valv
I

I

14
Throttle

Dr

V
lv8
I

Pre

Modil
lv8

15

3
151
2nd

j
Pre
u

Re1julato
Valva

@

n

No
Marked
er
0
8in

Primary

Gove
nor
V

I
Line

p
Go
erno
feed

p
euu

GOvernor

preuu

lEII
IIIII
To

que
con
8

t8
pres
He

Th
ottl

p
Second

Go
l
Io
vel
8

Fig
A
T
45
Oil

pressure
circuit

diagram
11

range
Low

gear

AT
31

3

Blowout

piston
by
directing
a

jet

of
air
into

hole
in

clutch
drum
See

Figure
AT
S
7

AT155

Fig
AT
87

Blowing
out

piston

Inspection

Refer
to

covering
topic
under

Front
Clutch

Assembly

Assembly
is

reverse
order
of
disas

sembly
Dip
all

parts
in

clean
auto

malic
transmission

fluid
before

as

sembling
Note
that
the
number
of

drive
and
driven

plates
varies
with

types
of
vehicles
For

details
refer
to

Service
Data

Specifications

I
After
rear

clutch
is

assembled

check

to
be

sure
that

clearance
be

tween

snap
ring
CD
and

retaining
plate

CV
is
held
within

prescribed
tolerances

See

Figure
A

T
S8

Specified
clearance

1
0

to
1
5

mm

0
039

to
0

059
in

AT1S6

Fig
A
T
88

Measuring
ring
to

plate

clearance

2

Testing
rear
clutch

Install
rear
clutch
on

oil

pump

cover

Blow
air
under

pressure
into
oil

hole
to
listen
for

definite
clutch

opera

tion

as
shown
in

Figure
AT
S9
AUTOMATIC
TRANSMISSION

AT157

Fig
AT
89

Testing
rear
clutch

Low
reverse
brake

Disassembly

I

Follow

steps
as

per
instructed
on

page
AT

38

2

Blowout

piston
by

directing
a

jet

of
air
into
oil

hole
in
clutch

piston

Inspection

I

Check
drive

plate
facing
for
wear

or

damage
if

necessary
replace
Refer

to
Service
Data

Specifications
for

limits

2
Test
if

piston
return

spring
is

not

weakened

Discard
if

weakened
too

badly
beyond
use

3

Replace
any
defective

parts
with

new

ones

Assembly

1
After
low

reverse

piston
is

installed
assemble
thrust

spring
ring

return

spring
thrust

washer
and
one

way
clutch
inner
race

With
the

aid
of

Hex

head
Extension
ST25570000

tighten
hex
head
slotted
bolt
1
3
to

1
8

kg
m
9
4

to
13
ft

Ib

2

Enter
dished

plate
driven

plate

drive

plate
and

retaining
plate
into

transmission

case
in

this
written
order

Install

snap
ring
to
secure

the
instal

lation

Note
The
number
of
drive
and
driven

plates
varies
with

types
of
vehi

cles
For

detailed
information

refer
to
Service
Data

Specifi

cations

AT
43
3

Without

disturbing
the
above

setting
check
to
be

sure
that
clearance

between

snap
ring
and

retaining
plate

is

held
within

specified
limits
If

nec

essary
try
with

other

plates
having

different
thickness
until
correct

clear

ance
is

obtained

Specified
clearance

O

SO
to
1

05
mm

0
031

to
0
041
in

4
Blow
under

pressure
air
into

oil

hole
in
low
reverse

brake
to

listen

for
definite
brake

operation
as
shown

in

Figure
AT
90

0j

L
J

1
1

I
1

I
Y

1
If

lY
v

A

we
1

a
II
I

7
r

AT158

Fig
AT
90

Testing
low
reverse

brake

Servo

piston

Disassembly

1
Blowout

piston
by
directing
a

jet

of
air
into

hole
in

release
side

of

piston

2
Remove

servo

piston
return

spring

Inspection

Check

piston
for
wear

damage
or

any
other
defects
which

might
inter

fere
with

proper
brake

operation

AT159

Fig
A
T
91
Removing
piston

Assembly

I

Prior
10

assemlbing
dip
all

parts

in

clean
automatic

transmission
fluid

Reverse

disassembly
procedure
to

assemble
brake

2
Use
extreme
care
to

avoid

dam

aging
rubber

ring
when

installing
seal

lace

3
Blow

under

pressure
air
from

apply
side
of

piston
to
lislen
for
defi

nite

piston

operation
as

shown
in

Figure
AT

93

4

With

appIy
side
of

piston
plugged

with

thumb
blow
air
under

pressure

into

cylinder
from
release

side
as

shown
in

Figure
AT
94
If
retainer

is

raised
a
little
it
is

an
indication
that

attaching
bolts

are
loosened

calling

for

retightening

Governor

Disassembly

l

Separate

governor
from

oil
dis

tributor

by

unscrewing

attaching
bolts

2
To

disassemble

secondary
gover

nor

remove

spring
seat

spring
and

secondary
governor
valve
from
valve

body
in

this

written
order
as
shown
in

Figure
AT
95

3

If

primary

governor
is

to
be
dis

assembled
for

any
purpose
remove

spring
seat

primary
governor
valve

spring
and

spring
eal
CHASSIS

I
Anchor
end

pin

2
Band

strut

3

Return

spring

4

Piston
stem

5
Band

servo

piston

6
Release

7

Apply

8

Servo

piston

relainer

9

Transmission
case

10

Band
brake

AT074

Fig
A
T
92
Sectional
view

of
servo

piston

Fig
A
T
93

Testing
piston

Apply
side

Fig
A
T
94

Testing
pi8ton

Rele
side

Inspection

I

Check
valve
for

defective
condi

tion

Replace
spring
if

found

weaken

ed
too

badly
beyond
use
Defective

piston
should

also
be

replaced
with

a

new
one

2
Examine
if

primary

governor

slides

freely
without

binding

3

To
determine

if

secondary
gover

nor
is
in

good
condition
blow

air

under

light
pressure
into
hole
at

A

to

listen
for
noise

like
a

model

plane

AT
44
r
To
control

valve

Governor

pressure

15

1

4

From
control

valve

Line

pressure
I

I

Primary

governor

2

Secondary
governor

3

Governor
valve

body
A
TogO

4
Oil

distributor

5

Output
shaft

Fig
A
T
95

Testing
secondary

governor

Assembly

Reverse

disassembly
procedure
to

assemble

governor

Note
Do
nol

confuse

primary
gover

nor

wilh

secondary
governor

After

instaDation
check
to
be

sure
that

spring
is
nol

de

flecled

Oil

pump

Disassembly

I

Free

pump
cover
from

pump

housing
by

removing
attaching
bolts

2
Take
out
inner
and

outer

gears

from

pump

houisng

Inspection

1

Inspect
gears
for
wear
or

damage

to

gear
leeth

Replace
rubber

ring
if

found

damaged
excessively

beyond

use

2

Using
a

straight
edge
and
feelers

measure

pump
and

gear
clearances
as

follows

Clearance
between
inner

or
outer

gear
and

pump
cover
See

Figure

AT
96

Standard
clearance

0
02

to
0
04
mm

0

0008
to
0
0016
in

Replace
if

going
over
0

08
mm

0
0031
in

AUTOMATIC
TRANSMISSIO
N

Valve

pring
chart

Installed

Wiredia
Mean
coil

No
of
Free

length

Valve
spring

mm
in
dia

active
coil

mm
in
Length
Load

mm
in

mm
in

kg
Ib

1
3
6
0

15
0
32
4

26
5
5
5

Manual
detent

0
0512
0
2362
1

276
1

043

12

1
2
10
5

13
0
43
0

23
5
2
8

Pressure

regulator

0
0472
0
4134
1
693
0

925
6
2

0
4

8
0
5
0
18
5
9
0
0
1

Pressure
modifier

0
0157
0
3150

0
728
0
3543
0
2

0
6
6
0

16
0
32
0
16
0
0
625
it
J

1st
2nd
shift

0
0236
0
2362
1

260
0

630
14
i

o

0
7
6
2
18

0
41
0
17
0
140

2nd
3
rd
shift

0
0276
0
2441
1

614
0
669
3
1

0
7
5
5
15

0
32
5
27
0
0
55

2nd
3rd

timing

0
0276
0
2165
1

280
1
063
1
2

Throttle
back

up
0

8
6
5
14

0
36
0
18

8
1
92

0

0315
0
2559
1417
0
740
4
2

0

55
5
0
12
0
22
0

12
5
0
60

Solenoid
downshift

0
0217

0
1969
0
866
0
492

1
3

0
55
5
0
16
0

33
5
21
0
0
60

Second
lock

0
0217
0
1969
1
319

0
827
1
3

0
9
5

6
14
0
26
8
19
0
2
19

Throttle
relief

0
0354
0
2205
1
055
0

748
4

8

0
2
4

8
15
0

21
5
11
5
0

01

Orifice
check

0
0078
0
1890
0
846

0
453
0
02

0
45
8
3
5
0
21
8
7
5
0

215

Primary

governor

0
0177
0
3268
0
858
0

2953
0
5

0
7
8
5
5
5
25
1
10
5
1
10

Secondary

governor

0

0276
0
3346
0
988
0
413
2
4

Free

length

L

U
d
As
ins
alled

I
t

LldnstjH
e

t
n
Ion

J
I
I
Assembly

Assembly
is

reverse
order
of

disas

sembly
However
observe
the
follow

ing
assembly
notes
Refer
to

Valve

Spring
Chart
and

illustration
in

as

sembling
valve

springs

Dip
all

parts
in

clean
automatic

transmission

fluid

before

assembly

Tighten
parts
to

specifications
whenever

designated
AT172

Fig
AT

106
Value

pring

AT
47
I

Slide
valve
into

valve

body
and
be

particularly
careful
that

they
are

not

forced
in

any
way

2
Install
side

plates

using
Torque

Driver
ST25I60000

See

Figure
AT

107

Tightening
torque

0
25
to
0
35

kg
m

1
9
to
2
5
ft
Ib

AUTOMATIC
TRANSMISSIO
N

TROUBLE
DIAGNOSES
AND
ADJUSTMENT

INSPECTION
AND
ADJUSTMENT

BEFORE
TROUBLE
DIAGNOSIS

Testing
instrument
for

inspection

Checking
oil
level

Inspection
and

repair
of
oil

leakage

Checking
engine

idling
rpm

Checking
and

adjusting
kick
down
switch

and
downshift
solenoid

Inspection
and

adjustment
of
manual

linkage

Checking
and

adjusting
inhibitor
switch

STALL
TEST

Stall

test

procedures

Judgement

As
the
troubles
on

the
automatic

transmission
can
be

mostly
repaired
by

doing
simple
adjustment
so
do

not

disassemble

immediately
if
the

auto

m
tic
transmission
is
in
trouble

Firstly
inspect
and

adjust
the
auto

matic
transmission
with

mounting
on

vehicle

by
observing
the

trouble

shooting
chart

If
the

trouble
could
not
be

solved

by
this

procedure
then

remove
and

disassemble
the
automatic
transmis

sion
It

is
advisable
to
check

overhaul

and

repair
each

point
in
the

order

itemized
in

the
trouble

shooting

chart

l
In
the

trouble

shooting
chart

the

diagnosis
items

are

arranged
in
the

order
from

easy
to

difficult
and
there

fore

please
follow
these
items

The

transmission
should
not
be
removed

unless

necessary

2
The

test
and

adjustment
for
trou

ble

diagnosis
should
be
made

on
the

basis
of
standard
values
and
the
data

should
be
recorded
ROAD
TEST

Car

speed
at

gear
shift

Checking
speed

changing
condition

Checking
items

during
speed
change

Shift
schedule

LINE
PRESSURE
TEST

Line

pressure
governor
feed

pressure

Judgement
in

measuring
line

pressure

TROUBLE
SHOOTING
CHART

Inspecting
items

Trouble

shooting
chart
for
3N71
B
Automatic

Transmission

Trouble

shooting
guide
for
3N718
Automatic

Transmission
CONTENTS

AT
49

AT
49

AT
49

AT
50

AT
50

AT
50

AT
51

AT
51

AT
51

AT51

AT
52

INSPECTION
AND

AD
JUSTMENT

BEFORE

TROUBLE

DIAGNOSIS

Testing
instrument
for

inspection

1

Engine
tachometer

2
Vacuum

gauge

3
Oil

pressure
gauge

It

is
convenient
to

install
these

instruments
in
a

way
that
allows

meas

urements
to
be
made

from
the
driver
s

seat

Checking
oil

level

In

checking
the
automatic
transmis

sion
the
oil

level
and

the
condition
of

oil
around

the
oil
level

gauge
should
be

examined

every
5

000
km
3
000

miles
These

steps
are

easy
and

effec

live

in
trouble

shooting
as
some

change
of
oil
conditions
are

linked

with

developed
troubles
in

many
cases

AT
49
AT
52

AT
52

AT
53

AT
53

AT
53

AT
53

AT
53

AT
54

AT
54

AT
54

AT
55

AT
5B

For
instance

Lack

of
oil
causes
defective

opera

tion

by
making
the
clutches
and

brakes

slip
developing
severe

wear

The

cause
of

this

operation
is
that

the

oil

pump
has

begun
to

suck
air

which

caused
oil

foaming
thus

rapidly

deteriora

ting
the
oil

quality
and

pro

ducing
sludge
and

varnish

Meanwhile
excessive
oil
is
also
bad

as
in
the

case
of

a
lack

of
oil
because

of
oil

foaming
by
being
stirred

up
by

the

gears
Moreover
in

high
speed

driving
with
excessive
oil
in
the
trans

mission
the
oil

often
blows
out
from

the
breather

I

Measuring
oil
level

When

checking
the
fluid
level
start

the

engine
and
run
it
until
normal

operating
temperatures
oil

tempera

ture
50
to

800e
122
to
176
F

Approximately
ten
minute

operation

will
elevate
the

temperature
to
this

range
and

enigne
idling
conditions

are
stabilized
Then

apply
the
brakes

and
move
the
transmission

shift
lever