Datsun 1968-1973 510 Owners Workshop Manual page 98

Chapter
6 Gearbox and automatic
transmission
r1
1 General descropt
on
The gearbox
fItted may be
of
eIther three
or
four speed
manual gearbox
or
automatiC transmission
dependmg
on
the
model
specification
Information
on
the automatiC transmiSSion
wIll be
found
later
on 10
thIs
chapter
The three speed gearbox
IS
fItted wIth synchromesh
on
all the
forward gears
For
qUIet operatIon
the gears
are
helical CUland
are In
constant mesh With the
laygear
The
reve
shdmg
gear
IS
able
to
engage WIth the
reverse
Idler
gear whIch
IS
driven from tha
laygear
The mput shaft takes the drive from the clutch and
vIa
constant
mesh gears
to
the laygear cluster
Dependmg
on
whIch
gear IS
selected drove
IS
then transmitted to
the mamshaft and
on
to
the
maIO
drive Ime
to
the flnsl drive
The mput
shaft
IS
mounted
10
the front
face
of the
gearbox
end
runs
In
a
smgle track
ball
bearong
Needle roller
bearongs
support the lay
gear on
the
layshaft
v
hlch
IS supported
at each
end
by
the
gearbox
caSIng End float of the
laygear
IS
controlled
by
selectIve thrust washers
The
maIO
shaft
assembly
IS
mounted
at
the front
10 a
needle
roller
bearmg
located
10
the
rear
of the
Input
shaft and
a
ball
race
at
the
rear
Selective fit clrcllps
are
used
to
adjust mdlvldual
gear and
bearing
end float
A remote
gearchange
system
s
used and mounted
on
the SIde
of the
steenng
column Rods
connect
the gear change lever
to
the
operatmg
levers located
on
the SIde of the
gearboX
casmg
Movement
IS
transferred
to
the gear
synchromser sleeves by rods
and shift forks
The
conltructlOn
of the four speed gearbox
IS
baSIcally
Indentlcal
to
that
prevIously
deSCribed for
the
three
speed
gearbox
With the
exception
of the gear selector
system
which
1
mounted
on
the floor
Gear change
lever movement
IS trans
erred
through a
strlkmg
rod
to
special gates
whIch
are
located
on
the shaft rods Movement
IS
then
via
shift forks
In contact
With the
synchronrser
sleeves
2 Gearbox removal and
replacement
1 The
procedure
for
removIng
the three and four
speed
gearboxes
IS
baSically
mdentlcal With the
exception
of diS
connecting
the gear
change
lever
2
The
best method of removmg the
gearbox
IS to
separate
the
gearbox bell housmg
from the engme and to
lower
the
gearbox
away from the undersIde of the Clr It
IS
recommended that
dUring
the
fInal stages
of
removal
assIstance
IS obtaIned
because
of the
weIght
3
D sconnect the battery
raIse
the
car
and place
on
axle stands
If
a
ramp IS
not
avaIlable
The
hIgher
the
car s
off the
ground
the
easIer It
WIll be
to
work underneath
4
Undo
the
gearbox
dram
plug
and dram the
011
Into a clean
contamer When all the 011 has dramed out
replace
the dram
plug
5 Refer
to
Chapter 9
and dIsconnect the handbrake
cable
at
the
equallser
pivot
6 Detach the
speedometer cable
from the gearbox
extensIon
housmg TIe the cable back
out
of the way
7 To gIve better
access
the exhaust
syltem
pre sllencer
should
be
rotated
Slacken
the
two centre
pIpe
clamps
and
turn
the
pre
SIlencer to the left
8 On PIck up moclels the exhault downplpe
must
be detached
from the exhaust
manifold
9 Refer to Chapter 7 and
remove
the
propeller
shaft
10 Locate the electrical cable connectIons to
the
neutral gear
SWItch third gear SWItch and
reverse gear sw
tch
Make
a note
of
the
cable colour
codmg and detach
11 D sconnect
the
gear
change
rocls from the
operatmg levers
and relay shaft
on
column gear
change
models
12 On floor
gear
change
moclels dIsconnect the gear
change lever
from the control
arm
13 D sconnect the relay shaft from between the
gearbox
and
i
J
1
h
1
r
t
7
i
ii
i
l
l
FIg
6 1 V
of
underside
of
car
showIng gearbox
r mountong
crossmamber
Sac 21
F g 6 2 DISCOnnectIng handbrake cable
Sac 21
FIg
6
3 DISCOnnectIng spaadometar
cable from extllllllon
hou
Ing
Sac 21