Daewoo Nubira. Manual - part 169

5B – 4

I

FIVE–SPEED MANUAL TRANSAXLE

DAEWOO V–121 BL4

J–42469

Shift Rod Remover

KM–519

Ring Installer

KM–520

Remover/Installer

KM–522

Installer

KM–525

Installer

KM–552

Fixture

KM–554

Installer

FIVE–SPEED MANUAL TRANSAXLE  5B – 5

DAEWOO V–121 BL4

DIAGNOSIS

ISOLATE NOISE

Identify the cause of any noise before attempting to repair
the clutch, the transaxle, or their related linkages.

Symptoms of trouble with the clutch or the manual trans-
axle include:

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A great effort required to shift gears.

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The sound of gears clashing and grinding.

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 Gear 

blockout.

Any of these conditions requires a careful analysis. Make
the following checks before disassembling the clutch or
the transaxle for repairs.

Road Travel Noise

Many noises that appear to come from the transaxle may
actually originate with other sources such as the:

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 Tires.

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 Road 

surfaces.

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 Wheel 

bearings.

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 Engine.

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 Exhaust 

system.

These noises may vary according to the:

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Size of the vehicle.

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Type of the vehicle.

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Amount of insulation used in the body of the ve-
hicle.

Transaxle Noise

Transaxle gears, like any mechanical device, are not ab-
solutely quiet and will make some noise during normal op-
eration.

To verify suspected transaxle noises:

1.  Select a smooth, level asphalt road to reduce tire

and resonant body noise.

2.  Drive the vehicle far enough to warm up all the lu-

bricants thoroughly.

3.  Record the speed and the gear range of the trans-

axle when the noise occurs.

4.  Check for noises with the vehicle stopped, but with

the engine running.

5.  Determine if the noise occurs while the vehicle op-

erates in:

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  Drive – under a light acceleration or a heavy

pull.

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  Float – maintaining a constant speed with a light

throttle on a level road.

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  Coast – with the transaxle in gear and the

throttle partly or fully closed.

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  All of the above.

Bearing Noise

Differential Side Bearing Noise
Differential side bearing noise and wheel bearing noise
can be confused easily. Since side bearings are pre-
loaded, a differential side bearing noise should not dimin-
ish much when the differential/transaxle is run with the
wheels off the ground.

Wheel Bearing Noise
Wheel bearings produce a rough growl or grating sound
that will continue when the vehicle is coasting and the
transaxle is in NEUTRAL. Since wheel bearings are not
pre–loaded, a wheel bearing noise should diminish con-
siderably when the wheels are off the ground.

Other Noise

Brinelling
A brinelled bearing causes a ”knock” or ”click” approxi-
mately every second revolution of the wheel because the
bearing rollers do not travel at the same speed as the
wheel. In operation, the effect is characterized by a low–
pitched noise.

A brinelled bearing is caused by excessive thrust which
pushes the balls up on the pathway and creates a triangu-
lar– shaped spot in the bearing race. A brinelled bearing
can also be caused from pressing one race into position
by applying pressure on the other race.

A false indication of a brinelled bearing occurs as a result
of vibration near the area where the bearing is mounted.
Brinelling is identified by slight indentations, resulting in a
washboard effect in the bearing race.

Lapping
Lapped bearing noise occurs when fine particles of abra-
sive materials such as scale, sand, or emery circulate
through the oil in the vehicle, causing the surfaces of the
roller and the race to wear away. Bearings that wear loose
but remain smooth, without spalling or pitting, are the re-
sult of dirty oil.

Locking
Large particles of foreign material wedged between the
roller and the race usually causes one of the races to turn,
creating noise from a locked bearing. Pre–loading regular
taper roller bearings to a value higher than that specified
also can result in locked bearings

Pitting
Pitting on the rolling surface comes from normal wear and
the introduction of foreign materials.

Spalling
Spalled bearings have flaked or pitted rollers or races
caused by an overload or an incorrect assembly that re-
sults in a misalignment, a cocking of bearings, or adjust-
ments that are too tight.

After completing these checks, refer to the ”Diagnosis
Chart” in this section.

5B – 6

I

FIVE–SPEED MANUAL TRANSAXLE

DAEWOO V–121 BL4

SYMPTOM DIAGNOSIS

Checks

Action

Check for a knock at low speeds.

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  Replace any worn drive axle CV joints.

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  Replace any worn side gear hub.

Check for a noise most pronounced on turns.

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  Correct any abnormalities in the differential gear.

Check for a clunk upon acceleration or deceleration.

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  Tighten any loose engine mounts.

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  Replace any worn drive axle inboard joints.

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  Replace any worn differential pinion shaft in the

case.

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  Replace any worn side gear hub in the case.

Check for a clunking noise in turns.

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  Replace any worn outboard CV joint.

Check for a vibration.

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  Replace any rough wheel bearing.

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  Replace any bent drive axle shaft.

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  Replace any out–of–round tires.

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  Balance any unbalanced tire.

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  Replace any worn CV joint in the drive axle shaft.

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  Correct an excessive drive axle angle by adjusting

the trim height.

Check for a noise in the NEUTRAL gear with the engine
running.

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  Replace any worn cluster bearing shaft.

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  Replace any worn clutch–release bearing.

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  Replace any worn input shaft cluster gears.

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  Replace any worn first–gear/bearing.

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  Replace any worn second–gear/bearing.

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  Replace any worn third–gear/bearing.

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  Replace any worn fourth–gear/bearing.

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  Replace any worn fifth–gear/bearing.

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  Replace any worn mainshaft bearings.

Check for a noise in the first gear (1) only.

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  Replace any chipped, scored, or worn first–gear

constant mesh gears.

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  Replace any worn first–second gear synchronizer.

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  Replace any worn first–gear/bearing.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

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  Adjust, repair, or replace the shift lever and the rods.

Check for a noise in the second gear (2) only.

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  Replace any chipped, scored, or worn second–gear

constant mesh gears.

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  Replace any worn first–second gear synchronizer.

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  Replace any worn second–gear/bearing.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

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  Adjust, repair, or replace the shift lever and the rods.

Check for a noise in the third gear (3) only.

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  Replace any chipped, scored, or worn third–gear

constant mesh gears.

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  Replace any worn third–fourth gear synchronizer.

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  Replace any worn third–gear/bearing.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

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  Adjust, repair, or replace the shift lever and the rods.

FIVE–SPEED MANUAL TRANSAXLE  5B – 7

DAEWOO V–121 BL4

Checks

Action

Check for a noise in the fourth gear (4) only.

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  Replace any chipped, scored, or worn fourth gear or

output gear.

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  Replace any worn third–fourth gear synchronizer.

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  Replace any worn fourth–gear/bearing.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

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  Adjust, repair, or replace the shift lever and the rods.

Check for a noise in the fifth gear (5) only.

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  Replace any chipped, scored, or worn fifth gear or

output gear.

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  Repair any worn fifth–gear synchronizer.

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  Replace any worn fifth–gear/bearing.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

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  Adjust, repair, or replace the shift lever and the rods.

Check for a noise in the reverse (R) gear only.

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  Replace any chipped, scored, or worn reverse idler

gear, idler–gear bushing, input gear, or output gear.

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  Replace any worn first–second gear synchronizer.

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  Replace any worn output gear.

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  Replace any worn differential–gear/bearing.

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  Replace any worn–ring gear.

Check for a noise in all gears.

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 Add 

sufficient 

lubricant.

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  Replace any worn bearings.

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  Replace any chipped, scored, or worn input–gear

shaft or output–gear shaft.

Check for the transaxle slipping out of gear.

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  Adjust or replace the linkage, as needed.

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  Adjust, repair, or replace any binding shift linkage.

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  Tighten or replace the input–gear bearing retainer, as

needed.

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  Repair or replace any worn or bent shift fork.

Check for a leak in the area of the clutch.

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  Repair the transaxle casing.

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  Replace any damaged release bearing guide.

Check for a leak at the center of the transaxle.

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  Repair the transaxle casing.

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  Repair the shift mechanism.

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  Replace the damaged backup lamp switch.

Check for a leak at the differential.

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  Adjust or replace the bearing retainers.

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  Tighten or replace the differential cover.

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  Adjust or replace the drive axle shaft seals.

Check for a hard shift.

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  Replace any damaged release–bearing guide.

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  Adjust, repair, or replace the shift mechanism.

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  Adjust, repair, or replace the clutch–release system.

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  Replace any chipped, scored, or worn fifth–gear syn-

chronizer.

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  Replace any chipped, scored, or worn first–second

gear synchronizer.

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  Replace any worn third–fourth gear synchronizer.

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  Adjust, repair, or replace the shift lever and the rods.