MG MGB User Manual

Fe
THE
OVERDRIVE
(TYPE
L.H.)
Section
Fc.l'
GENERAL
DESCRIPTION
The
Laycock Type
L.H. Overdrive
■tted
between
the
gearbox and
propeller shaft
is
a
self-contained
gear
unit
which
provides
a
higher
overall
gear
ratio
than
that
given by
the ■nal
drive.
The
overdrive
gears
consist
of
a
central
sun
wheel
and three
planet
gears
which
mesh
with
an
internally toothed
annulus.
Fitted
inside the
annulus
is
a
uni-directional
clutch.
A sliding clutch-member
is
secured
to
the
sun
wheel
and
is
free
to
move
forward
and
rearward
on
the
sun
wheel
splines.
Attached
to
a
ball bearing,
secured
on
the
sliding
+
clutch
by
a
circlip,
is
a
static
thrust
ring.
The thrust
ring
is
actuated
by
two
hydraulic
pistons and
returned by
primary
and
secondary
return
springs.
An electrically
operated
solenoid
valve,
mechanical
pump,
relief
valve,
and low
pressure
valve
comprise
the
main
components
of the hydraulic
system.
Overdrive
engaged
With the
overdrive
switch selected
the
solenoid
is energized
and the
ball valve
is
held
in
the
closed
position
by
the
solenoid
rod.
The
input
shaft
to
the
overdrive
unit
carries
a cam
which
operates
the
overdrive
oil
pump.
The
pump
draws
oil from
Fig.
Fc.1
Direct
drive
Sump.
Magnet ■lters.
.
Gauze
filter.
Pump.
Third
motion
shaft
(gearbox).
PPWPT‘
6. Control
switch.
7. Solenoid
operating
valve.
8.
Low
pressure
valve.
9. Relief
valve.
10. Operating
pistons.
11.
Oil
return
to
sump.
Fig.
Fc.2
Overdrive
engaged
Fc.4
MGB.
Issne
1. 15676

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English