1993 CHEVROLET DYNASTY differential

HYDRAULIC SYSTEM CONTROL VALVES INDEX
page page
General Information ....................... 10
Hydraulic System Service Procedures ......... 11 Pressure Differential Warning Light Switch
...... 10
GENERAL INFORMATION
All models equipped with a Bendix Antilock 4 Brake
System have 2 screw-in type proportioning valves.
There is 1 valve for each individual rear wheel hydrau-
lic brake line. The proportioning valves are mounted
directly into the rear brake outlet ports of the modula-
tor assembly (Fig. 1).
The proportioning valves limit brake pressure to the
rear brakes after a certain pressure (split point) is
reached. This improves front to rear brake balance
during normal braking. Screw-in proportioning valves can be identified by
numbers stamped on the body of the valve. The first
digit represents the slope, the second digit represents
the split (cut-in) point, and the arrow represents the
flow direction of the valve. Be sure numbers listed
on a replacement valve are the same as on the
valve that is being removed. See (Fig. 2) for detail of
the valve identification.
PRESSURE DIFFERENTIAL WARNING LIGHT
SWITCH
The hydraulic brake system, on vehicles equipped
with the Bendix Antilock 4 Brake System is split
diagonally. The left front and right rear brakes are on
one hydraulic system, and the right front and left
rear are on another. Both systems are routed
through, and hydraulically separated by the Pressure
Differential Switch (Fig. 3) mounted in the hydraulic brake tube junction block. The function of the Pressure
Differential Switch is to alert the driver of a malfunc-
tion in the brake hydraulic system.
If hydraulic pressure is lost in one system, the
warning light switch will activate the RED brake
warning light on the instrument panel, when the brake
pedal is depressed. At this point the brakes hydraulic
system requires immediate service. However, since the
brake systems are split diagonally the vehicle will
retain 50% of its stopping capability in the event of a
failure in either half. The warning light switch is the latching type. It
will automatically center itself after the repair is
made and the brake pedal is depressed.
Fig. 1 Rear Brake Proportioning Valve Location On Modulator Assembly
Fig. 2 ABS PROPORTIONING VALVE IDENTIFICA- TION
Fig. 3 Pressure Differential Warning Light Switch InJunction Block.
5 - 10 BRAKES Ä

(2) The voltage output from each of the wheel
speed sensors is verified to be within the correct op-
erating range. If a vehicle is not set in motion within 3 minutes
from the time the ignition switch is turned to the on
position. The solenoid valve test is bypassed but the
pump/motor is activated briefly to verify that it is op-
erating correctly.
WARNING SYSTEMS OPERATION
The ABS system uses an Amber Antilock Warning
Lamp, located in the instrument cluster. The purpose
of the warning lamp is discussed in detail below. The Amber Antilock Warning Light will turn on
whenever the CAB detects a condition which results
in a shutdown of the Antilock brake system. The
Amber Antilock Warning Lamp is normally on until
the CAB completes its self tests and turns the lamp
off (approximately 1-2 seconds). When the Amber
Antilock Warning Light is on, only the Antilock
brake function of the brake system if affected. The
standard brake system and the ability to stop the car
will not be affected when only the Amber Antilock
Warning Light is on.
NORMAL OPERATION OF WARNING LAMP
With ignition key turned to the Crank position, the
Red Brake Warning Lamp and Amber Antilock
Warning Lamp will turn on as a bulb check. The
Amber Antilock Warning Lamp will stay on for 1-2
seconds then turn off, once verification of Antilock
Brake System self diagnosis is completed.
ANTILOCK BRAKE SYSTEM COMPONENTS
The following is a detailed description of the Ben-
dix Antilock 4 Brake System components. For infor-
mation on servicing the Four Wheel Disc Brake
System, see the standard Brake section in the Front
Wheel Drive Car, chassis service manual.
MODULATOR ASSEMBLY
WARNING: THE ONLY COMPONENTS OF THE
MODULATOR ASSSEMBLY THAT ARE SERVICE-
ABLE, ARE THE 2 PROPORTIONING VALVES,
BLEED SCREWS AND THREAD SAVERS. THE RE-
MAINING COMPONENTS OF THE MODULATOR AS-
SEMBLY ARE NOT INTENDED TO BE
SERVICEABLE ITEMS. NO ATTEMPT SHOULD BE
MADE TO REMOVE OR SERVICE ANY OTHER COM-
PONENTS OF THE MODEULATOR ASSEMBLY.
The Modulator Assembly (Fig. 1) is located under
the battery tray and is covered with an acid shield.
The Modulator Assembly contains the following com-
ponents for controlling the Antilock brake system. 4
Build/Decay Valves, 4 Shuttle Orifices, 2 Fluid
Sumps, 2 Accumulators, and a Pump/Motor assem- bly. Also attached to the Modulator Assembly are 6
brake tubes which are connected to a 12 way junc-
tion block. The junction block (Fig. 2) is mounted to
the left frame rail below the master cylinder in the
same location as the non ABS equipped combination
valve. The wheel brake lines are attached to the sys-
tem via the connector block.BUILD/DECAY VALVES
There are 4 Build/Decay valves, one for each
wheel. In the released position they provide a fluid
path direct to the wheel brakes. In the actuated (de-
cay) position, they provide a fluid path from the
wheel brakes to the sump. The Build/Decay valves
are spring loaded in the released (build) position.
SHUTTLE ORIFICE
There are 4 Shuttle Orifice Valves, one for each
wheel. The Shuttle Orifice Valve is a hydraulically
actuated valve which shuttles when the Build/Decay
valve is actuated. Actuating of the Build/Decay valve
causes a pressure differential to be created across the
Shuttle Orifice Valve. This acts like placing an ori-
Fig. 1 Modulator Assembly
Fig. 2 Antilock Brake Junction Block
5 - 16 ANTILOCK 4 BRAKE SYSTEM Ä

fice (restriction) in the line between the wheel and
the Build/Decay Valve. This restriction provides a
controlled build rate to each wheel brake during an
Antilock stop. The Shuttle Orifice Valve will remain
in the orificed position until the ABS cycle is com-
plete. When the ABS cycle has been completed the
Build/Decay valves will return to their released posi-
tion which will equalize the pressure across the
Shuttle Orifice Valves. When the pressure equalizes,
the spring loaded Shuttle Orifice valves will return
to the unrestricted position.
FLUID SUMPS
There are two Fluid Sumps in the Hydraulic As-
sembly, one for the primary and secondary hydraulic
circuits. The Fluid Sumps store the brake fluid that
is decayed from the wheel brakes during an ABS cy-
cle. This fluid is then pumped to an accumulator
and/or the hydraulic system in order to provide build
pressure. The typical pressure in the sumps is 50 psi,
during ABS operation only.
HYDRAULIC SPRING ACCUMULATOR
The Hydraulic Spring Accumulators (Fig. 3) (one
on each circuit) are used to store pressurized hydrau-
lic brake fluid during ABS operation only. This fluid
is used during hard braking when the ABS system is
activated, to supplement brake pressure when re-
quired. During normal Non ABS brake operation
there is NO pressurized brake fluid stored in the ac-
cumulators. The Hydraulic Spring Accumulators are
not a serviceable part of the Modulator Assembly
and should never be removed from the assembly.
PRESSURE DIFFERENTIAL SWITCH
The Pressure Differential Switch on the Bendix An-
tilock 4 Brake System is located on the frame rail
mounted brake hydraulic tube junction block. This
switch functions the same as the Pressure Differential
Switch located in the combination valve on standard
non ABS brake system. The pressure differential
switch monitors the primary and secondary hydraulic
brake circuits for a difference in pressure. A pressure
difference greater than 225 psi., will move and latch
the switch, grounding the Red Brake Warning Light
circuit. This will in turn, turn on the Red Brake
Warning Light in the instrument panel to warn the
driver of a pressure loss in one of the brake hydraulic
systems. This pressure differential switch is a replace-
able item of the junction block assembly. The Red
Brake Warning Light only indicates a problem
with the foundation brake hydraulic system and
not the Antilock system.
PUMP/MOTOR ASSEMBLY
The Modulator Assembly contains 2 Pump Assem-
blies, one each for the primary and secondary hydrau-
lic circuits. Both pumps are driven by a common
electric motor which is part of the Modulator Assembly.
The pumps take brake fluid from the sumps to supply
pressure to the accumulators or hydraulic system via
the shuttle orifice during an Antilock stop. The motor
only runs during an ABS stop and is controlled by the
CAB via the Pump/Motor Relay. The Pump/Motor
Assembly is not a serviceable item. If it requires
service the Modulator Assembly must be replaced.
PROPORTIONING VALVES
Two Proportioning Valves (Fig. 4) are used in the
Bendix Antilock 4 Brake System, one for each of the
rear wheel brake hydraulic circuits. The Proportioning
Valves function the same as in a standard brake
system. The Proportioning Valves are located on the
side of the modulator assembly (Fig. 1). Each rear
wheel hydraulic brake line, is connected to an indi-
vidual proportioning valve.
Fig. 3 Hydraulic Spring Accumulator
Fig. 4 Proportioning Valve Identification
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 17

(4) If equipped, remove the 2 bolts (Fig. 4) attaching
speed control vacuum reservoir to battery tray. Then
remove vacuum reservoir (Fig. 4) from the battery tray.
Vacuum lines (Fig. 4) do not need to be removed
from vacuum reservoir. (5) Remove the 4 bolts attaching battery tray (Fig.
5) to frame rail and fender shield of the vehicle.
Then remove battery tray.
(6) Remove battery acid shield, (Fig. 6) from the
ABS modulator assembly.
(7) Remove the 6 tube nuts (Fig. 7), attaching hy-
draulic brake line tube bundle to modulator assem-
bly, thread savers and proportioning valves. Then
remove the 6 hydraulic brake lines as an assembly,
from the modulator assembly. (8) Remove electrical connector from the brake
pressure differential warning switch on hydraulic
junction block (Fig. 8). (9) Remove the primary and secondary hydraulic
brake tubes (Fig. 9) going from the master cylinder
to the junction block, from both master cylinder and
junction block. (10) Remove the brake hydraulic tube going to the
vehicle's left front wheel from the junction block. (11) Remove the 6 hydraulic brake tubes at the hy-
draulic junction block, coming from the antilock mod-
ulator assembly.
Fig. 5 Battery Tray And Attaching Bolts
Fig. 6 ABS Modulator Assembly Acid Shield
Fig. 2 Battery Heat Shield And Hold Down Clamp
Fig. 3 Battery Tray Shield
Fig. 4 Speed Control System Vacuum Reservoir
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 35

(12) Remove hydraulic brake tube assembly rout-
ing bracket, from the engine mounting bracket (Fig.
10). (13) Remove the 6 hydraulic brake tubes and rout-
ing bracket as an assembly from the vehicle.
INSTALL (1) Install the 6 hydraulic brake tubes, clips and
routing bracket as an assembly into the vehicle. (2) Align the 6 hydraulic brake tubes with their
correct locations on the junction block. Thread the 6
brake line tube nuts by handinto the junction block
tube ports. Then torque all 6 brake tube nuts to 18
N Im (159 in.lbs.).
(3) Install the primary and secondary hydraulic
brake tubes, from master cylinder to junction block
(Fig. 9). Then torque the brake line tube nuts at both
the master cylinder and junction block to 18 N Im
(159 in. lbs.). (4) Install the hydraulic brake tube assembly rout-
ing bracket onto the engine mounting bracket (Fig. 10). Torque the brake tube routing bracket attaching
bolt to 11 N
Im (95 in. lbs.).
(5) Align the 6 hydraulic brake lines with their ap-
propriate fitting locations on the modulator assembly
(Fig. 11). Thread the 6 brake line tube nuts by hand
into proportioning valves and thread savers on mod-
ulator assembly. (6) Using a crow foot and torque wrench (Fig. 12),
torque the 6 hydraulic brake line tube nuts to 18
N Im (159 in. lbs.).
(7) Using approved battery jumper cables, attach
battery, to the vehicles negative and positive battery
cables (Fig. 13). (8) Bleed the vehicles base brake and Antilock
brake hydraulic systems. Refer to Bleeding Bendix
Fig. 7 Hydraulic Brake Line Connections To Modulator Assembly
Fig. 8 Pressure Differential Switch Assembly
Fig. 9 Brake Tubes From Master Cylinder To Junction Block
Fig. 10 Brake Tube Routing Bracket
5 - 36 ANTILOCK 4 BRAKE SYSTEM Ä

TRANSAXLE
CONTENTS
page page
41TE FOUR SPEED AUTOMATIC TRANSAXLE . 85
41TE FOUR SPEED TRANSAXLE HYDRAULICSCHEMATICS ........................ 170
41TE ON-BOARD DIAGNOSTICS .......... 145
A-523, A-543, and A-568 MANUAL TRANSAXLE ........................... 1 SPECIFICATIONS
...................... 183
THREE SPEED TORQUEFLITE AUTOMATIC TRANSAXLE .......................... 35
THREE SPEED TRANSAXLE HYDRAULIC SCHEMATICS ........................ 162
A-523, A-543, and A-568 MANUAL TRANSAXLE INDEX
page page
Bearing Adjustment Procedure .............. 31
Differential Bearing Preload Adjustment ........ 33
Gearshift Linkage Adjustment (Cable Operated) . . 2
General Information ........................ 1 In-Car Transaxle Disassemble/Assemble
........ 4
Out of Car TransaxleÐDisassemble and Assemble . 6
Subassembly-Recondition .................. 15
Transaxle Removal and Installation ............ 5
GENERAL INFORMATION
Safety goggles should be worn at all times
when working on these transaxles. All manual
transaxles use SAE 5W-30 engine oil, meeting SG
and/or SG-CC qualifications, as the lubricant in order
to reduce wear. This 5-speed manual transaxles combine gear reduc-
tion, ratio selection, and differential functions in one
unit. It is housed in a die-cast aluminum case (Fig. 1). All shift forks are cast iron.
Do not interchange 1-2
or 5th shift fork pads with the 3-4 shift fork pads.
All synchronizers use a winged strutdesign that
prevents the struts from popping out of position. If any synchronizer is to be disassembled, mark
all parts so that they will be reassembled in the
same position.
CAUTION: 1-2 synchronizer assembly components
must NOT be interchanged with any other synchro-
nizer assembly. Do not interchange with previous
model years transaxles; they will NOT function cor-
rectly.
A-523 AND A-543 MANUAL TRANSAXLE
The A-523 manual transaxle is used in all 4-cylinder
applications, except high output turbocharged engines.
The A-543 manual transaxle is used only with V-6
engines. To reduce wear, the manual transaxle uses SAE
5W-30 engine oil as the lubricant. Gear ratios for the A-523 and A-543 are as follows:
1stÐ3.31, 2cdÐ2.06, 3rdÐ1.36, 4thÐ0.97, 5thÐ0.71,
ReverseÐ3.14. The final drive ratio is 3.77.
CAUTION: All gears and shafts must not be inter-
changed with previous model years; they will not
function correctly.
Fig. 1 External Transaxle Components
Ä TRANSAXLE 21 - 1

CAUTION: Be sure crossover bellcrank does NOT
move when tightening adjusting screw (Fig. 10).
CAUTION: Proper torque to the crossover cable ad-
justing screw is very important (Fig. 10).
(6) Remove lock pin from gearshift housing and re-
install lock pin (so long end is up) in gear shift hous-
ing. Tighten lock pin to 8 N Im (70 in. lbs.).
(7) Check for shift into first and reverse.
(8) Gearshift mechanism and cables are now func-
tioning properly.
IN-CAR TRANSAXLE DISASSEMBLE/ASSEMBLE
The following items can be serviced without remov-
ing the transaxle from the vehicle:
² Gear shift housing
² Synchronizers
² Intermediate shaft speed gears
² Input shaft
² Reverse idler gear and shaft
² Shift forks and pads
² Shift rails ²
Roller detents
² Speedometer pinion
² All external covers
Observe following procedure:
(1) Disconnect negative cable from battery.
(2) Remove both shift cables from shift cover levers.
(3) Remove left front wheel and tire assembly and
left splash shield. (4) Place drain pan under transaxle and remove
transaxle rear end cover. (5) Push out the fifth fork roll pin and slide the fifth
fork and synchronizer sleeve off the rail/hub. (6) Remove the fifth hub snap ring, hub assembly
and speed gear. (7) Remove fifth gear nut and fifth input gear.
(8) Remove the bearing retainer plate, interlock
plate and shuttles.
CAUTION: Before removing the gearshift housing
assembly, reverse the lock pin (so the long end is
down) and insert lock pin into the same threaded
hole. This procedure will save time when the gear
shift housing assembly is reinstalled. (9) Remove selector shaft housing bolts (note the two
pilot bolts) and remove housing. (10) Remove roller detents and springs, noting that
the rollers align with the shift rails. (11) Push out the 1-2 and 3-4 lug roll pins, remove
the reverse pivot lever and fifth rail C-Clip. If a roll
pin or C-Clip falls, be sure to remove it from the
bottom of the case. (12) Pull out the fifth shift rail and remove the fifth
shift lug and interlock pin. If the pin falls, be sure to
remove it from the bottom of the case. (13) Remove the intermediate shaft ball bearing
snap ring and the bearing support plate. (14) Remove reverse shift rail and lug assembly.
(15) Remove the reverse idler shaft and gear assem-
bly. (16) Rotate the 1-2 shift lug and rail, and 3-4 shift
lug towards the front of the vehicle. (17) Firmly grasp both the input and intermediate
shaft assemblies and pull them out of the transmission
with the 1-2 and 3-4 shift rails, lugs and forks. The differential assembly can only be serviced
by removing the complete transaxle from the
vehicle because bearing preload must be reset. The components listed in the first paragraph can now
be serviced. Refer to the appropriate subassembly
recondition section.
To reassemble the transaxle in the vehicle, reverse
the above procedure using the proper sealants. Fill the
transaxle with SAE 5W-30 engine oil to the bottom of
the fill hole in the end cover.
Fig. 9 Install Cables
Fig. 10 Adjusting Crossover Cable
21 - 4 TRANSAXLE Ä

OUT OF CAR TRANSAXLEÐDISASSEMBLE AND
ASSEMBLE
DIFFERENTIAL
Fig. 1 Remove or Install 2 Extension Outer Bolts
Fig. 2 Remove or Install 3 Differential Bearing Retainer Outer Bolts
Fig. 3 Remove or Install Differential Cover Bolts
Fig. 4 Remove Differential Cover
Fig. 5 Differential Cover Removed
Fig. 6 Remove or Install 2 Extension Bolts
21 - 6 TRANSAXLE Ä