Opel Frontera UBS. Manual - part 1421

7A–18

AUTOMATIC TRANSMISSION (4L30–E)

Chart 9c: Coastdown Harsh Shift Or Clunk At 3–2 Downshift

Step

Action

Yes

No

1

Check line pressure. Refer to Line Pressure Test in this section.

Was line pressure normal?

Go to Step 2

Use Chart 15b:

Possible Causes

of High Line

Pressure in this

section

2

Does DTC P1850 set?

Diagnose P1850

first

Replace band

apply solenoid

(PWM) (323)

Chart 10: Intermittent 4TH TO 2ND Gear Downshift At Steady Speed

Step

Action

Yes

No

1

Check for consistent speed sensor reading with scan tool.

Was the reading correct?

Replace mode

switch for

intermittent

contact.

Go to Step 2

2

1. Check for wiring harness damage or short to ground. If OK, go

to (2).

2. Check transmission speed sensor connections. If OK, go to

(3).

3. Replace transmission speed sensor.

Was the replacement complete?

—

Replace speed

sensor.

Chart 11: Engine Flare At Shifting During Turning Only (Usually With Warm Engine)

Step

Action

Yes

No

1

Check for oil leaks at transmission.

Was the problem found?

Replace

transmission oil

filter and gasket

—

Chart 12: Engine Flare During 1–2 Or 2–3 Shift

Step

Action

Yes

No

1

Check line pressure. Refer to Line Pressure Test in this section.

Was line pressure normal?

Go to Step 2

Use Chart 15a:

Possible Causes

of Low Line

Pressure in this

section

2

1. Check for a stuck 1–2 accumulator valve (320).
2. Check for servo piston (106) leaks.
3. Check for a stuck band apply solenoid (323).

Was line pressure normal?

Repair or replace

—

7A–19

AUTOMATIC TRANSMISSION (4L30–E)

Chart 13: Shudder Only During Torque Converter Clutch (TCC) Applying

Step

Action

Yes

No

1

1. TCC shudder is one of the most commonly misdiagnosed

conditions in an automatic transmission.  The key to
diagnosing TCC shudder is to note when it happens and under
what conditions.  Once the TCC has been fully applied, it is
nearly impossible to make it shudder.  TCC shudder (short
burst of noise normally less than 1 second) will only occur
during clutch applying.  It is not a steady state condition.

2. Drive until whole drivetrain is at normal operating temperature.

– On 4WD vehicles, the test must be performed with transfer

case selector lever in “2H” position.

– Shudder is a short burst of noise normally less than 1 second

in duration, and can be induced by the following maneuver:

3. From coast condition at 50 mph in “D” range (Normal mode),

depress the throttle to 1/4-1/3 throttle. If present, shudder will
occur within 5 seconds together with TCC application.(The
scan tool may be used to determine the exact time of TCC
applying)

Was the problem found?

Replace

transmission fluid

and filter (remove

both pans) and

flush cooler lines.

Replace

converter

assembly and

O-ring on turbine

shaft

Perform

mechanical

inspection of

other drivetrain

components.

Chart 14: Possible Causes Of Transmission Noise

CAUTION: Before checking transmission for what
is believed to be transmission noise, ensure
presence and positioning of insulating plugs, pads
etc. Also make sure that noise does not come from
other drivetrain components.

Condition

Possible cause

Correction

Whine or Buzz

Oil level low

Fill with ATF, check for external
leaks.

Plugged or restricted oil filter

Inspect oil filter.
Replace oil filter or ATF as necessary.

Damaged oil filter gasket

Replace oil filter gasket.

Knocking noise from front of
transmission

Loose bolts (Converter to flex plate)

Tighten to specifications.

transmission.

Cracked or broken flex plate

Replace flex plate.

Converter damaged

Replace converter.

Knocking noise while driving, mostly
on acceleration.

Transmission mount loose or broken

Tighten mount bolts or replace
transmission mount.

Cooler line mounts loose or broken

Tighten or replace cooler line
mounts.

Cooler lines touching body or frame

Repair or replace as necessary.

Knocking noise when vehicle is
stationary

Loose flex plate mounting bolts

Tighten to specifications.

stationary.

Cracked or broken flex plate

Replace flex plate.

Damaged converter

Replace converter.

7A–20

AUTOMATIC TRANSMISSION (4L30–E)

Chart 15a: Possible Causes of Low Line Pressure

Step

Action

Yes

No

1

Check oil level.

Was the problem found?

Fill with ATF

Go to Step 2

2

Check for defective throttle position sensor.

Was the problem found?

Replace throttle

position sensor

Go to Step 3

3

Check for plugged, loose, or damaged oil filter (79).

Was the problem found?

Inspect oil filter,

tighten bolts or

replace oil filter

(79)

Go to Step 4

4

Check for a stuck force motor plunger (404). (Adapter case valve
body)

Was the problem found?

Replace force
motor plunger

(404)

Go to Step 5

5

Check for a stuck feed limit valve (412). (Adapter case valve body)

Was the problem found?

Replace feed limit

valve (412)

Go to Step 6

6

Check for loose converter bolts (4 & 5).

Was the problem found?

Tighten converter

bolts (4 & 5)

Go to Step 7

7

Check for a stuck pressure regulator valve (208). (Oil pump)

Was the problem found?

Replace pressure

regulator valve

(208)

Go to Step 8

8

Check for a stuck boost valve (205).(Oil pump)

Was the problem found?

Replace boost

valve (205)

Go to Step 9

9

Check for blocked intermediate oil passages to pressure
regulator valve. (Oil pump)

Was the problem found?

Replace oil pump

Go to Step 10

10

Check for defective oil pump (9, 201, 202 & 209).

Was the problem found?

Replace oil pump

Go to Step 11

11

Check for internal leaks.

– Check balls missing or out of location in valve bodies
– Seals cut or damaged
– Gaskets defective, etc.

Was the problem found?

Install balls, or

correct ball

location

Replace seals

Replace gaskets

—

7A–21

AUTOMATIC TRANSMISSION (4L30–E)

Chart 15b: Possible Causes Of High Line Pressure

NOTE: If transmission is operating in backup mode, high
line pressure will be present.

Step

Action

Yes

No

1

Check for defective throttle position sensor.

Was the problem found?

Replace throttle

position sensor.

Go to Step 2.

2

Check for a stuck force motor plunger (404). (Open
circuit/intermittent) (Adapter case valve body)

Was the problem found?

Replace force
motor plunger

(404)

Go to Step 3

3

Check for a stuck feed limit valve (412). (Adapter case valve body)

Was the problem found?

Replace force
motor plunger

(412)

Go to Step 4

4

Check converter bolts (4 & 5).

Was the problem found?

Tighten converter

bolts (4 & 5)

Go to Step 5

5

Check for a stuck pressure regulator valve (208). (Oil pump)

Was the problem found?

Replace pressure

regulator valve

(208)

Go to Step 6

6

Check for a stuck boost valve (205). (Oil pump)

Was the problem found?

Replace boost

valve (205)

Go to Step 7

7

Check for internal leaks.

– Check balls missing or out of location in valve bodies
– Seals cut or missing
– Gaskets defective, etc.

Was the problem found?

Install balls, or

correct ball

location

Replace seals

Replace gaskets

—