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7-20
GROUP 7- AUTOMATIC TRANSMISSION
FORWARD CLUTCH (Front)
Apply air pressure to the
trans-
mission case forward clutch passage
(Fig.
15).
A dull thud can be heard
when the clutch piston is applied. If
no noise is heard, place the finger tips
on the clutch and again apply air
pressure to the forward clutch pas-
sage. Movement of the piston can
be felt as the clutch is applied.
Caution: Forward and governor
passages are common, therefore if
there is excess
air
leakage from
governor, clutch operation may not
be audible.
GOVERNOR
Apply air pressure, to the control
pressure to governor passage and
listen for a sharp clicking or whistling
noise. The noise indicates governor
valve movement.
REVERSE-HIGH CLUTCH (Rear)
Apply air pressure to the reverse-
high clutch passage
(Fig.
15).
A dull
thud indicates that the reverse-high
clutch piston has moved to the ap-
plied position. If no noise is heard,
place the finger tips on the clutch
drum and again apply air pressure to
detect movement of the piston.
INTERMEDIATE SERVO (Front)
Hold the air nozzle in the inter-
mediate servo apply passage (Fig.
15).
Operation of the servo is indi-
cated by a tightening of the inter-
mediate band around the drum.
FIG. 15 - Air Pressure
Checks
Continue to apply air pres!>ure into
the intermediate servo apply pas-
sage, and
introduce
air pressure
into the intermediate servo release
passage.
The intermediate servo
should release the band against the
appJy pressure.
LOW-REVERSE SERVO (Rear)
Apply air to the low reverse servo
apply passage (Fig.
15).
The low re-
verse band should tighten around the
drum if the servo is operating pro-
perly. CAUTION: DO NOT AP-
PLY AIR PRESSURE TO THE
SERVO UNLESS IT IS AS AS-
SEMBLED TO mE TRANS-
MISSION OR mE SERVO MAY
BE DAMAGED.
EJ
IN-CAR ADJUSTMENTS AND REPAIR
PROCEDURE FOR CHECKING
FLUID LEVELS
Refer to Part 7-1, Section 2.
It is unnecessary to drain the con-
verter and transmission as a normal
service item.
The transmission is air and water
cooled and therefore keep the under-
side free from mud, etc. otherwise
overheating may result.
PRELIMINARY ADJUSTMENTS
FLUID LEVEL
Incorrect transmission fluid level
can have the following effects, al-
though they may
be
attributable to
other malfunctions:-
(a)
No drive in "D", "1", "2"
or "R".
(b) Slip and squawk or judder
on full throttle starts in
"D", "1 ", "2" or "R".
(c)
Overheating due to high
fluid level during sustained
high speeds.
ACCELERATOR LINKAGE AND
DOWN SHIFT VALVE CONTROL
CABLE
If the accelerator linkage is in-
correctly adjusted preventing full
movement of the accelerator pedal,
the carburettor butterfly will not
open fully resulting in poor engine
performance and insufficient control
pressure in
relation
to accelerator
pedal movement.
It is therefore essential to ensure
that the throttle butterfly fully opens
as the accelerator linkage is also con-
neated to the automatic transmission
down shift valve by a cable, it is
essential for the linkage and cable to
be
correctly adjusted, otherwise the
If the servos do not operate, dis-
assemble, clean and inspect them to
locate source of the trouble.
If the air pressure applied to any
clutch passage fails to operate the
clutch or operates more than one
clutch at once, remove, and with
air pressure, check fluid passages
in the case, pump output and
primary shaft to detect cross leakage
or obstruction. If the passages are
intact and clear, remove the clutch
assemblies and clean and inspect
the malfunctioning clutch to locate
the trouble.
DIAGNOSIS GUIDE (Table
2)
The Transmission Diagnosis
Guide lists the most common trou-
ble symptoms that may
be
found in
the transmission, and gives the items
that should
be
checked to find the
cause of the trouble.
The items to check for each
trouble symptom are arranged
in
a
logical sequence which should
be
followed for quickest results. The
letter symbols for each item are ex·
plained in the Key to the Diagnosis
Guide.
If
items A, B, C, D, E, and the
stall test have already been checked
during the preliminary checks and
adjustments, they need not
be
re-
peated when following the Diagnosis
Guide.
automatic transmission will not oper-
ate satisfactorily and premature fail-
ure may result.
Incorrect adjustment of the down-
shift valve control cable can have the
following results:-
(a) Excessive bump when
"D"
or "R" is engaged.
(b) No drive in "D".
(c) Delayed or no first to
second change.
(d) Slip on first to second
change.
(e) Delayed or no second to
third change.
(f) Slip or engine "run-up" on
second to third change.
(g) Bumpy gear changes.
(h) Slip and squawk or judder
on full throttle starts in
"D".
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