21 • 2
TRANSMISSION
•
FLUID
TEMPERATURE
THERMO-SWITCHES
Fourth
gear
operation in the diesel A518 is also
controlled
by two temperature sensitive thermo-
switchos.
. .. •
The
first
thermo-switch is the engine coolant tem-
perature
switch.
This
switch
prevents overdrive
fourth
gear
operation when engine coolant tempera-
ture is below approximately 65° F.
The second thermo-switch
directly
monitors trans-
mission
fluid
temperature. The
switch
'
will
either
downshift
the transmission to
third
gear,
or prevent
a 3-4 upshift when
fluid
temperature
exceeds
270-275°
F.
The
f|uid
temperature
switch
is located in a
boss
built
intp
the cooler outlet
line.
The
boss
and
switch
are located approximately 2-3 inches
from
the outlet
line
fitting
in the transmission
case.
The engine coolant and
fluid
temperature switches
are in
circuit
with
the overdrive
control
switch
in the
instrument
panel. A detailed schematic showing
switch
circuitry
and connection is provided in Group
14 of-this supplement.
SERVICE
PROCEDURE
AND SPECIFICATION
CHANGES
Specifications
and repair procedures for the diesel
and gas engine versions
of
the A518 are basically the
same.
The
only
component requiring different service
methods is the new overrunning
clutch.
Service procedures for the new overrunning
clutch
are included in this supplement section. Refer to the
1991
shop manual for all other A518 service proce-
dures.
SERVICING
THE NEW
OVERRUNNING
CLUTCH
CLUTCH
COMPONENT
REMOVAL
(1)
Disassemble the transmission down to the low-
reverse drum as described in Group 21 of the 1991
manual.
(2)
Remove the
snap
ring
that retains the
low-re-
verse
drum on the overdrive piston retainer hub.
(3)
Slide the low-reverse drum off the retainer hub
and out of the rear band
(Fig.
1).
(4)
Note that the overrunning
clutch
race
will
re-
main
on the splines of the low-reverse drum after re-
moval
(Fig. 2). The race is a permanent press fit
on the hub splines. Do not attempt to remove the
race.
(5)
Remove the overrunning
clutch
assembly (Fig.
3).
The assembly can be removed
without
displacing
the rollers and springs if
care
is exercised. Note po-
sition
of the rollers and springs for assembly refer-
ence.
(6)
Examine the
clutch
cam (Fig. 3). If the cam is
worn,
damaged, or loose, replace it. Refer to the pro-
cedure in the A518 section, Group 21 of the 1991
manual.
J9221-8
Fig.
2
Overrunning
Ctutch
Race
Position
(7)
Examine the overrunning
clutch
race. Replace
the low-reverse drum and
race
as an assembly if ei-
ther the race, or drum is
worn
or damaged.
Also
re-
place the entire assembly if the
race
is loose on the
splines of the drum hub.
CLUTCH
COMPONENT
INSTALLATION
(1)
Lubricate the overdrive piston retainer hub,
clutch
race,
clutch
cam, and overrunning
clutch
roll-
ers
with
Mopar ATF Plus, or Dexron II®.
(2)
If any of the overrunning
clutch
rollers and
springs
came
out of the retainer, reinstall them as
follows:
Install
and
seat
the spring in the retainer
first.
Then insert the
roller
between the spring and
retainer stop as shown (Fig. 4).
Verify
that each
roller
and spring are
fully
seated
before proceeding.
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