Chrysler 1991 Service Manual Supplement page 130

•
TRANSMISSION 21 - 1
TRANSMISSION
C O N T E N T S
page
FLUID TEMPERATURE THERMO-SWITCHES . 2
GENERAL INFORMATION 1
GENERAL SPECIFICATIONS-DIESEL A518 ...3
GOVERNOR WEIGHT ASSEMBLY 1
PLANETARY GEARS 1
SERVICE PROCEDURE AND SPECIFICATION
CHANGES 2
SERVICING THE NEW OVERRUNNING
GENERAL INFORMATION
A heavy duty version of the A518, 4-speed auto-
matic transmission has been released for use with
the Cummins turbo diesel engine.
Major differences between diesel and gas engine
versions of the A518 involve the:
• transmission case
• torque converter
• planetary gears
• transmission shafts
• governor weight assembly
• overrunning clutches
• fluid temperature thermo-switch
TRANSMISSION CASE
The diesel A518 transmission case has a larger
converter housing to accommodate the 12.2 in. torque
converter. The housing bolt pattern is also different
being drilled for the Cummins engine block.
TORQUE COUVERTER
A three element, non-lockup torque converter is
used for diesel engine applications. Converter diame-
ter is 12.2 in. (310 mm).
The converter is not a serviceable component. Re-
place the converter as an assembly if diagnosis indi-
cates this is necessary.
TRANSilSSiON 0VERRU1N1NG CLUTCH AND
LOW-REVERSE DRUM
A new design overrunning clutch is used in diesel
versions of the A518 transmission. The individual
components consist of: the cam, which is still pressed
into the case; the clutch race which is now pressed
onto the hub of the low-reverse drum; and the new
cage-type overrunning clutch assembly.
The new overrunning clutch assembly will also
be phased into gasoline engine versions of the
A727/A518 transmission. Production release is
scheduled for sometime in January or February
1991.
page
CLUTCH
• i 3 Q 1 3 3 0 i 3 C O O U y j i O O O t ) » 3 0 0 B 3 B
2
TORQUE CONVERTER . . . .
1
TRANSMISSION AND OVERDRIVE COMPOUNDER
CLUTCH PACKS
1
TRANSMISSION CASE
1
TRANSMISSION OVERRUNNING CLUTCH AND
LOW-REVERSE DRUM 1
The new clutch assembly contains more rollers and
springs than previous models. It also features a cage-
type retainer for the springs and rollers. The sepa-
rate retainer used previously is eliminated.
The clutch race is now pressed onto the hub of the
low-reverse drum. The race is not removable and is
serviced only as part of the drum.
The new clutch cam is essentially the same as the
prior design. The tools and service techniques for re-
placing new and prior design clutch cams are the
same. Refer to the procedures in Group 21 of the
1991 manual.
PLANETARY GEARS
The transmission and overdrive planetary gear car-
riers in the diesel A518 are heavy duty components.
The transmission planetary carriers have four pin-
ion gears. The carrier in the overdrive compounder
has five pinion gears. The heavy duty planetary
units are unique to the diesel version of the A518.
TRANSMISSION AND OVERDRIVE COMPOUNDER
CLUTCH PACKS
Clutch packs used in the diesel version of the A518
contain the following number of discs and plates:
• transmission front/rear clutch has 4 discs and 5
steel plates
• overdrive clutch has 5 discs and 6 steel plates
• overdrive direct clutch has 8 discs and 9 steel
plates
GOVERNOR WEIGHT ASSEMBLY
The governor weight assembly in the diesel A518
is made of alloyed brass. The diesel weight assembly
is easily identified by the distinctive gold color of the
alloyed material.
The heavier weight assembly provides the shift
points needed to offset lower operating speeds of a
diesel engine.
The alloyed weight assembly is unique to the diesel
A518. I t is not interchangeable with the weight as-
semblies used in gas engine versions of the A518.