Isuzu Trooper (2000 year). Service manual - part 372

7A–8

AUTOMATIC TRANSMISSION (4L30–E)

General Diagnosis Procedure

F07RT038

7A–9

AUTOMATIC TRANSMISSION (4L30–E)

Preliminary Inspection Chart

F07RY00001

7A–10

AUTOMATIC TRANSMISSION (4L30–E)

Checking Transmission Fluid Level
and Condition

Checking fluid level and condition (color and odor) at
regular intervals will provide early diagnosis information
about the transmission. This information may be used to
correct a condition that, if not detected early, could result
in major transmission repairs.
IMPORTANT:

When new, automatic transmission fluid

is red in color. As the vehicle is driven, the transmission
fluid will begin to look darker in color. The color may
eventually appear light brown.
A dark brown color with burnt odor may indicate
excessive fluid deterioration and signal a need for fluid
change.

Fluid Level

When adding or changing fluid, use only DEXRON 



–III.

Refer to Maintenance and Lubrication in General
Information section for maintenance information and
servicing interval.

CAUTION: DO NOT OVERFILL.
Overfilling will cause foaming, loss of fluid, abnor-
mal shifting and possible damage to the transmis-
sion.

1. Park the vehicle on level ground and apply the parking

brake firmly.

2. Check fluid level with engine running at idle.

NOTE: Be sure that transmission fluid temperature is
below 30

°

C (86

°

F).

3. Move the selector lever through all gear ranges.
4. Move the selector lever to “Park”.
5. Let engine idle for 3 minutes and open the overfill

screw (1).

6. Add released transmission fluid until it flows out over

the overfill screw opening.

7. Let engine idle until a fluid temperature between 32

°

C

(90

°

F) and 57

°

C (135

°

F) is reached, then close the

overfill screw (1).

Torque: 38 N

•

m (28 lb ft)

NOTE: To prevent fluid leaks, the overfill screw and oil
drain screws gasket must be replaced each time these
screws are removed.

NOTE: Check transmission fluid temperature with scan
tool.

Minimum fluid level 

→

 57

°

C (135

°

F)

Maximum fluid level 

→

 32

°

C (90

°

F)

242RW003

CAUTION: Do not open overfill screw with engine
stopped.

CAUTION: DO NOT CHECK FLUID LEVEL UNDER
THESE CONDITIONS:

D

Immediately after driving at sustained highway
speeds.

D

In heavy city traffic during hot weather.

D

If vehicle is towing a trailer.

If the vehicle has been operated under these conditions,
shut the engine off and allow the vehicle to “cool” for thirty
(30) minutes. After the cool down period, restart the
vehicle and continue from step 2 above.

7A–11

AUTOMATIC TRANSMISSION (4L30–E)

Fluid Condition

FLUID CONDITION

NORMAL*

CONTAMINATED

COLOR

RED OR LIGHT

BROWN

BROWN

NON–TRANSPARENT

/ PINK

BROWN

DRAIN 

REQUIRED?

NO

YES

YES

YES

CONTAMINA–

TION

NONE

Very small amount of
foreign material in
bottom of pan

Contamination by
coolant or other source

Large pieces of metal
or other foreign
material in bottom of
pan

CORRECT

LEVEL AND

CONDITION

1. LOW LEVEL:

A. Add fluid to

obtain proper
level & check for
external leaks. 

B. Correct cause of

leak.

2. HIGH LEVEL:

– Remove excess

fluid

– Remove both pans
– Change filter
– Flush cooler
– Add new fluid
– Check level

– Repair/replace

radiator cooler

– Transmission

overhaul required

– Check for:

D

Damaged plates
and seals

D

Contaminated
solenoids

– Flush cooler
– Add new fluid
– Check level

– Transmission

overhaul required

– Flush cooler and

cooler lines

– Add new fluid
– Check level

*Fluid should be changed according to maintenance
schedule.

Test Driving

Some 4L30–E automatic transmission complaints will
require a test drive as a part of the diagnostic procedure.
Some codes will not set unless the vehicle is moving. The
purpose of the test drive is to duplicate the customer’s
complaint condition and set a current Powertrain Control
Module (PCM) trouble code. Perform this procedure
before each 4L30–E automatic transmission repair, and
again after repairs are made.
IMPORTANT:

D

Duplicate the condition under which the customer’s
complaint was observed.

D

Depending on the complaint, the line pressure gauge
and the scan tool may be required during the test
drive.

D

During the test drive, it is important to record all
necessary data from the areas being monitored, for
use in diagnosis. Also listen for and note any unusual
noises.

The following procedure should be used to test drive
4L30–E automatic transmission complaint vehicles:

1. Turn the ignition ON without starting the engine.

Check that the “CHECK TRANS” lamp comes on for
approximately 2 seconds and then goes out and
remains out.

D

If the lamp is flashing, GOTO Check Trans Indicator
in Transmission Control System (4L30–E) section.

D

If no serial data is present, GOTO OBD System
Check. Refer to Driveability and Emissions in
Engine section.

D

If the lamp stays ON or stays OFF, GOTO “Check
Trans” Check in Transmission Control System
(4L30–E) section.

2. Drive the vehicle. During the test drive, be sure that

the transmission achieves normal operating
temperature (approx. 20 minutes).
Allow the transmission to go through all of its gear
ranges, checking shift timing and firmness. Duplicate
the owner ’s complaint condition as closely as
possible during the test drive.

3. If, during the test drive, the “CHECK TRANS” lamp

comes on, use the scan tool to check for trouble
codes.

4. If, during the test drive, a problem is felt, but the

“CHECK TRANS” lamp does not come on and no
trouble codes are present, drive the vehicle with the
PCM disconnected (manually shifting the vehicle).

D

In Manual L, the vehicle operates in first gear.

D

In Manual 2, the vehicle operates in third gear.

D

In Manual 3 or “D”, the vehicle operates in fourth
gear.

If the problem still exists with the PCM disconnected,
refer to Mechanical/Hydraulic Diagnosis in this
section.

5. If no problem has been found at this point, check all

underhood connections that supply power to the PCM
and ignition fuses. Physically and visually inspect all
the PCM harness connectors for loose or corroded
terminals. Inspect the PCM ground points.