
ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 45
DAEWOO V–121 BL4
CLUTCH PLATE DIAGNOSIS
Composition Plates
Dry the plate and inspect the plates for the following condi-
tions :
S Pitting
S Flaking
S Wear
S Glazing
S Cracking
S Charring
Chips or metal particles embedded in the lining
Replace a composition plate which shows any of these
conditions.
Steel Plates
Wipe the plates dry and check the plates for heat discolor-
ation. If the surfaces are smooth, even if colorsmear is in-
dicated, you can reuse the plate. If the plate is discolored
with hot spots or if the surface is scuffed, replace the plate.
Important : If the clutch shows evidence or extreme heat
or burning, replace the springs.
Causes of Burned Clutch Plates
The following conditions can result in a burned clutch
plate:
S Incorrect usage of clutch plates.
S Engine coolant in the transaxle fluid.
S A cracked clutch piston.
S Damaged or missing seals.
S Low line pressure.
S Valve problems.
– The valve body face is not flat
– Porosity between channels
– The valve bushing clips are improperly installed.
– The check balls are misplaced.
S The seal rings are worn or damaged
Engine Coolant in Transaxle
Notice : Antifreeze will deteriorate the O–ring seals and
the glue used to bond the clutch material to the pressure
plate. Both conditions may cause transaxle damage.
Perform the following steps if the transaxle oil cooler has
developed a leak, allowing engine coolant to enter the
transaxle:
1. Because the coolant will attach to the seal material
causing leakage, disassemble the transaxle and
replace all rubber type seals.
2. Because the facing material may become sepa-
rated from the steel center portion, replace the
composition faced clutch plate assemblies.
3. Replace all nylon parts including washers.
4. Replace the torque converter.
5. Thoroughly clean and rebuild the transaxle, using
new gaskets and oil filter.6. Flush the cooler lines after you have properly re-
paired or replaced the transaxle.
COOLER FLUSHING AND FLOW
TEST
Notice : You must flush the cooler whenever you receive
a transaxle for service. Cooler flushing is essential for
SRTA installation, major overhaul, whenever you replace
a pump or torque converter, or whenever you suspect that
the fluid has been contaminated.
After filling the transaxle with fluid, start the engine and run
for 30 seconds. This will remove any residual moisture
from the oil cooler. Disconnect the return line at the trans-
axle and observe the flow with the engine running. If the
fluid flow is insufficient, check the fluid flow by disconnect-
ing the feed line at the cooler. Observe the flow with the
engine running.
S If the flow from the cooler return line at the trans-
axle is insufficient, check the flow rate from the feed
line to the cooler. BLockage exists in the transaxle
or the cooler.
S If the flow from the transaxle feed line to the cooler
is insufficient, the transaxle is the cause of the fluid
flow problem.
S If the flow the transaxle feed line to the cooler is
insufficient, but flow from the cooler return line to
the transaxle is insufficient, inspect the cooler pipes
and fittings. Then repeat the cooler flushing proce-
dure. If the flow is still insufficient, replace the cool-
er.
TRANSAXLE FLUID LEVEL SERVICE
PROCEDURE
This procedure is to be used when checking a concern
with the fluid level in a vehicle. A low fluid level will result
in slipping and loss of drive/ reverse or delay on engage-
ment of drive/ reverse when the vehicle is cold.
The vehicle is first checked for transaxle diagnostic mes-
sages on the scan tool. If the oil level is low, it is possible
to register a vehicle speed signal fault.
The vehicle is to be test driven to determine if there is an
abnormal delay when selecting drive or reverse, or loss of
drive. One symptom of low fluid level is a momentary loss
of drive when driving the vehicle around a corner. Also
when the transaxle fluid level is low, a loss of drive may oc-
cur when the transaxle fluid temperature is low.
When adding or changing transaxle fluid use only ESSO
LT 71141 automatic transaxle fluid or other approved
fluids. The use of incorrect fluid will cause the performance
and durability of the transaxle to be severely degraded.
Fluid Level Diagnosis Procedure
1. If the vehicle is at operating temperature allow the
vehicle to cool down for two hours, but no greater
than four hours. Or if the vehicle is at cool status,
start the engine and allow the engine to idle for
approximately 5 minutes (825~875 rpm), if pos-

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 49
DAEWOO V–121 BL4
Functional Check Procedure
Inspect
1. Install a tachometer or scan tool.
2. Operate the vehicle unit proper operating tempera-
ture is reached.
3. Drive the vehicle at 80 to 88km/h (50 to 55 mph)
with light throttle(road load).
4. Maintaining throttle position, lightly touch the brake
pedal and check for release of the TCC and a slight
increase in engine speed(rpm).
5. Release the brake slowly accelerate and check for
a reapply of the Lock up clutch and a slight de-
crease in engine speed(rpm).
Torque Converter Evaluation
Torque Converter Stator
The torque converter stator roller clutch can have one of
two different type malfunctions :
A. Stator assembly freewheels in both directions.
B. Stator assembly remains Locked up at all times.
Condition A – Poor Acceleration Low
Speed
The car tends to have poor acceleration from a stand still.
At speeds above 50 to 55km/h(30 to 35mph), the car may
act normal. If poor acceleration is noted, it should first be
determined that the exhaust system is not blocked, and
the transaxle is in 1st(First) gear when starting out.
If the engine freely accelerates to high rpm in N(Neutral),
it can be assumed that the engine and exhaust system are
normal. Checking for poor performance in ”Drive” and ”Re-
verse” will help determine if the stator is freewheeling at all
times.
Condition B – Poor Acceleration High
Speed
Engine rpm and car speed limited or restricted at high
speeds. Performance when accelerating from a standstill
is normal. Engine may overheat. Visual examination of the
converter may reveal a blue color from overheating.
If the converter has been removed, the stator roller clutch
can be checked by inserting two fingers into the splined in-
ner race of the roller clutch and trying to turn freely clock-
wise, but not turn or be very difficult to turn counter clock-
wise.
Noise
Torque converter whine is usually noticed when the ve-
hicle is stopped and the transaxle is in ”Drive” or ”Re-
verse”. The noise will increase when engine rpm is in-
creased. The noise will stop when the vehicle is moving or
when the torque converter clutch is applied because both
halves of the converter are turning at the same speed.
Perform a stall test to make sure the noise is actually com-
ing from the converter :1. Place foot on brake.
2. Put gear selector in ”Drive”.
3. Depress accelerator to approximately 1200rpm for
no more than six seconds.
Notice : If the accelerator is depressed for more than six
seconds, damage to the transaxle may occur.
A torque converter noise will increase under this load.
Important : This noise should not be confused with pump
whine noise which is usually noticeable in P (Park), N
(Neutral) and all other gear ranges. Pump whine will vary
with pressure ranges.
The torque converter should be replaced under any of the
following conditions:
S External leaks in the hub weld area.
S Converter hub is scored or damaged.
S Converter pilot is broken, damaged or fits poorly
into crankshaft.
S Steel particles are found after flushing the cooler
and cooler lines.
S Pump is damaged or steel particles are found in the
converter.
S Vehicle has TCC shudder and/or no TCC apply.
Replace only after all hydraulic and electrical diag-
noses have been made.(Lock up clutch material
may be glazed.)
S Converter has an imbalance which cannot be cor–
rected. (Refer To Converter Vibration Test Proce-
dure.)
S Converter is contaminated with engine coolant con-
taining antifreeze.
S Internal failure of stator roller clutch.
S Excess end play.
S Heavy clutch debris due to overheating (blue con-
verter).
S Steel particles or clutch lining material found in fluid
filter or on magnet when no internal parts in unit are
worn or damaged(indicates that lining material
came from converter).
The torque converter should not be replace if :
S The oil has an odor, is discolored, and there is no
evidence of metal or clutch facing particles.
S The threads in one or more of the converter bolt
holes are damaged.
–correct with thread insert.
S Transaxle failure did not display evidence of dam-
age or worn internal parts, steel particles or clutch
plate lining material in unit and inside the fluid filter.
S Vehicle has been exposed to high mileage(only).
The exception may be where the Lock up clutch
damper plate lining has seen excess wear by ve-
hicles operated in heavy and/or constant traffic,
such as taxi, delivery or police use.
Lock–Up Clutch Shudder Diagnosis
The key to diagnosing lock–up clutch(TCC) shudder is to
note when it happens and under what conditions.

5A1 – 50IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
TCC shudder should only occur during the APPLY and/or
RELEASE of the Lock up clutch.
While TCC Is Applying Or Releasing
If the shudder occurs while TCC is applying, the problem
can be within the transaxle or torque converter.
Something is not allowing the clutch to become fully en-
gaged, not allowing clutch to release, or is trying to release
and apply the clutch at the same time. This could be
caused by leaking turbine shaft seals, a restricted release
orifice, a distorted clutch or housing surface due to long
converter bolts, or defective friction material on the TCC
plate.
Shudder Occurs After TCC Has Applied :
In this case, most of the time there is nothing wrong with
the transaxle! As mentioned above, once the TCC has
been applied, it is very unlikely that will slip. Engine prob-
lems may go unnoticed under light throttle and load, but
become noticeable after TCC apply when going up a hill
or accelerating, due to the mechanical coupling between
engine and transaxle.
Important : Once TCC is applied there is no torque con-
verter assistance. Engine or driveline vibrations could be
unnoticeable before TCC engagement.
Inspect the following components to avoid misdiagnosis of
TCC shudder and possibly disassembling a transaxle and/
or replacing a torque converter unnecessarily :
S Spark plugs – Inspect for cracks, high resistance or
broken insulator.
S Plug wires – Lock in each end, if there is red dust
(ozone) or black substance (carbon) present, then
the wires are bad. Also look for a white discolor-
ation of the wire indicating arcing during hard accel-
eration.
S Distributor cap and rotor – look for broken or un–
crimped parts.
S Coil – look for black on bottom indication arcing
while engine is misfiring.
S Fuel injector – filter may be plugged.
S Vacuum leak – engine won’t get correct amount of
fuel. May run rich or lean depending on where the
leak is.S EGR valve – valve may let it too much unburnable
exhaust gas and cause engine to run lean.
S MAP sensor – like vacuum leak, engine won’t get
correct amount of fuel for proper engine operation.
S Carbon on intake valves – restricts proper flow or
air/fuel mixture into cylinders.
S Flat cam – valves don’t open enough to let proper
fuel/air mixture into cylinders.
S Oxygen sensor – may command engine too rich or
too lean for too long.
S Fuel pressure – may be too low.
S Engine mounts – vibration of mounts can be multi-
plied by TCC engagement.
S Axle joints – checks for vibration.
S TPS – TCC apply and release depends on the TPS
in many engines. If TPS is out of specification, TCC
may remain applied during initial engine starting.
S Cylinder balance – bad piston rings or poorly seal-
ing valves can cause low power in a cylinder.
S Fuel contamination – causes poor engine perfor-
mance.
TCM INITIALIZATION PROCEDURE
When one or more operations such as shown below are
performed, all learned contents which are stored in TCM
memory should be erased after the operations.
S When A/T H/W is replaced in a vehicle,
S When a used TCU is installed in other vehicle,
S When a vehicle condition is unstable (engine RPM
flare, TPS toggling and so on; at this kind of unsta-
ble conditions, mis–adaptation might be done).
1. Connect the Scan 100 with a DLC connector in a
vehicle.
2. Turn ignition switch ON.
3. Turn the power on for the Scan 100.
4. Follow the ”TCM LEARNED INITIALIZE” procedure
on the Scan 100 menu.
Notice : Before pushing ”Yes” Button for TCM initialization
on the Scan 100 screen, make sure that the condition is
as follows:
Condition :
1. Engine idle.
2. Select lever set ”P” range.

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 227
DAEWOO V–121 BL4
2. Find the disc set’s thickness. Refer to the below
table.
PF
Disc set’s Thickness
3.01~3.19mm1.8mm
3.20~3.48mm2.1mm
3.49~3.88mm2.5mm
3.89~4.08mm2.7mm
4.09~4.30mm3.0mm
PE is 4.20mm so, the disc set’s thickness is
3.0mm.
3. Replace clutch B’s setting disc. (3.0mm)
TORQUE CONVERTER HOUSING
Disassembly and Assembly Procedure
1. Remove the torque converter bolts.
2. Hit the torque converter housing lightly.
3. Remove the torque converter housing.
Installation Notice
S First pre–tighten the bolts in the following or-
der.(7,20)(12,23)(16,4)
Tighten
Tighten the bolts to 15 NSm (11 lb–ft).
S Then, tighten the bolts in the following order. (15,3)
(16,4) (14,5) (13,23) (12,22)(11,21)
(10,20) (9,19) (8,18) (7,17) (6) (1,2)
S Last, in numerical order, tighten the bolts all the
way.(123)
Tighten
Tighten the bolts to 23 NSm (17 lb–ft).
4. Take out the metal gasket.
5. Take out the paper gasket.
6. Remove the oil filter bolt and oil filter.
Installation Notice
Tighten
Tighten the oil filter bolt to 10 NSm (89 lb–in).

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 233
DAEWOO V–121 BL4
To engage the lock–up clutch, the direction of flow is modi-
fied (reversed) via a valve in the hydraulic selector unit. At
the same time, the space behind the lock–up clutch piston
is vented. The oil pressure passes from the turbine cham-
ber to the lock–up clutch piston and presses it against the
converter’s cover. The turbine is thus blocked by way of
the linings between the piston and cover, and permits rigid
through drive with no slip (or reduced slip if controlled) to
the mechanical stage of the transaxle.
Fluid Pump
The fluid pump is located between the torque converter
and the transaxle case and is driven directly by the torque
converter. The pump sucks the fluid through a filter and de-
livers it to the main pressure regulator valve of the control
system. Excess fluid flows back to the pump. The fluid
pump fulfills the following functions:
S Generates line pressure.
S Delivers fluid under pressure to the torque convert-
er, thus preventing air bubbles in the fluid.
S Induces a flow of fluid through the torque converter
in order to eliminate heat.
S Supplies fluid pressure to the hydraulic control sys-
tem.
S Supplies fluid pressure to the shift components.S Lubricates the transaxle with fluid.
Pump Housing
1. Disc
2. Shaft seal
3. Stator shaft
4. Pump wheel
5. Pump ring gear
6. Dowel pin
Planetary Gears
The ZF 4HP 16 automatic transaxle is equipped with a one
sun gear, 4 planetary gears, planetary carrier, ring gear.
Each gear is located one directly behind the other and are
linked together. In other words, front ring gear is perma-
nently linked to rear planet carrier, front planet carrier is
linked to rear ring gear.
The individual gear ratios are obtained by linking together
the gear set elements in different ways by means of
clutches and brakes.
On the 4HP 16, the power flow is directed into the plane-
tary gear set via rear planet carrier or rear sun gear, or via
both simultaneously, depending on the gear in question.
The output is always via the front planet carrier.

SECTION : 6B
POWER STEERING PUMP
TABLE OF CONTENTS
SPECIFICATIONS6B–1 . . . . . . . . . . . . . . . . . . . . . . . . . .
General Specifications 6B–1. . . . . . . . . . . . . . . . . . . . .
Fastener Tightening Specifications 6B–1. . . . . . . . . . .
DIAGNOSIS6B–2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Steering Pump Diagnosis 6B–2. . . . . . . . . . . . .
MAINTENANCE AND REPAIR6B–3 . . . . . . . . . . . . . . .
ON–VEHICLE SERVICE 6B–3. . . . . . . . . . . . . . . . . . . . . Serpentine Accessory Drive Belt 6B–3. . . . . . . . . . . . .
Pump Assembly 6B–4. . . . . . . . . . . . . . . . . . . . . . . . . . .
UNIT REPAIR 6B–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pump 6B–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GENERAL DESCRIPTION AND SYSTEM
OPERATION6B–8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Steering Pump 6B–8. . . . . . . . . . . . . . . . . . . . . .
SPECIFICATIONS
GENERAL SPECIFICATIONS
ApplicationDescription
LubricantPower Steering Fluid DEXRON®–II or III
Pressure
– without EVO8330 kPa ~ 8820 kPa (1208 psi ~ 1279 psi)
– with EVO8500 kPa ~ 8960 kPa (1233 psi ~ 1299 psi)
FASTENER TIGHTENING SPECIFICATIONS
ApplicationNSmLb–FtLb–In
Air Filter Housing Assembly Bolts6–53
High–Pressure Hose Fitting2821–
Power Steering Pump Bolts2518–
Right Side Power Steering Pump Bracket Bolts3526–

POWER STEERING PUMP 6B – 3
DAEWOO V–121 BL4
MAINTENANCE AND REPAIR
ON–VEHICLE SERVICE
SERPENTINE ACCESSORY DRIVE
BELT
Removal Procedure
1. Remove the air filter housing assembly bolts and
the air intake tube.
2. Remove the air filter housing assembly from the
vehicle.
3. Use a wrench to turn the tensioner bolt clockwise,
compressing the tensioner, and releasing the ten-
sion on the serpentine accessory drive belt.
4. Remove the serpentine accessory drive belt.

6B – 4IPOWER STEERING PUMP
DAEWOO V–121 BL4
Installation Procedure
1. Use a wrench to turn the tensioner bolt clockwise,
compressing the tensioner, and releasing the ten-
sion on the serpentine accessory drive belt.
2. With the wrench in place on the tensioner bolt, loop
the serpentine accessory drive belt loosely over the
pulleys.
3. Slip the belt over the tensioner.
4. Remove the wrench from the tensioner bolt and the
belt will tighten itself.
5. Install the air filter housing assembly into the ve-
hicle.
6. Install the air intake tube and the air filter housing
assembly bolts.
Tighten
Tighten the air filter housing assembly bolts to 6 NSm
(53 lb–in).
PUMP ASSEMBLY
Removal Procedure
1. Remove the serpentine accessory drive belt. Refer
to ”Serpentine Accessory Drive Belt” in this sec-
tion.
2. Disconnect the electrical connector at the Electronc
Vaariable Orifice (EVO) solenoid actuator.