2004 ISUZU TF SERIES check transmission fluid

7A3-12 ON-VEHICLE SERVICE (AW30 –40LE)

Manual Shifting Test
NOTE: With this test, it can be determined whether the
trouble lies within the electrical circuit or is a mechanical
problem in the transmission.
1. Disconnect TCM connector
Inspect manual driving operation
2. Inspect manual driving operation
Check that the shift and gear positions correspond
with the table.
If the “L", “2", “3" and “D" range gear positions are
difficult to distinguish, do perform the following road
test.
While driving, shift through the “L", “2", “3" and “D"
ranges. Check that the gear change corresponds to
the gear position.
If any abnormality is found in the above test, do
perform the stall, time lag or gear change tests.



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3. Connect TCM connector
With the engine off, connect the TCM connector.


Stall Test



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The object of this test is to check the overall
performance of the transmission and engine b
y
measuring the maximum engine speeds at the “D" and
“ R" ranges.
NOTE:
1. Perform the test at normal operation fluid
temperature (50 – 80 
C or 122 – 176 
F).
2. Do not continuously run this test longer than 5 seconds.

7A3-14 ON-VEHICLE SERVICE (AW30 –40LE)

Measure Time Lag
1. Fully apply the parking brake.
2. Start the engine. Check idling speed (A/C OFF).
3. Shift the shift lever from “N" to “D" range. Using a
stopwatch, measure the time it takes from shifting
the lever until the shock is felt.
Time lag: Less than 0.7 seconds
4. In same manner, measure the time lag for “N"


“R".
Time lag: Less than 1.2 seconds
Evaluation
1. If “N" 
“ D" time lag is longer than specified:

Line pressure too low
 Forward clutch malfunction
 No.2 one-way clutch not operating properly
2. If “N" 
“ R" time lag is longer than specified:

Line pressure too low
 Direct clutch malfunction
 No.3 brake malfunction
3. If both time lag is longer than specified:

Line pressure too low

Hydraulic Test



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Preparation

1. Warm up the transmission fluid.
2. Remove the transmission case test plug and mount the hydraulic pressure gauge.
Oil pressure gauge: J –29770 –A
NOTE: Perform the test at normal operation fluid
temperature (50 – 80 
C or 122 – 176 
F).

ON-VEHICLE SERVICE (AW30 –40LE) 7A3-21

Transmission Fluid Level and Condition
Inspection
Park vehicle on level ground and set parking brake.
With the engine idling, move the shift lever through all
positions from “P" to “L", then return to position “P".
Check to see if the level of fluid comes to “HOT" range
of about 80 
 

C (176 
 

F) on the dipstick gauge.
If the level of fluid is too low, replenish to bring it to
maximum level in “HOT" range.
Inspection of fluid condition. If the ATF is black o
r
smells burnt, replace it.



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UNIT REPAIR (AW30–40LE) 7A4–37
Diaassembly, Inspection and
Reassembly of minor Components
NOTE: The instructions here are organized so that you
work on only one component group at a time.
This will help avoid confusion from similar-looking parts
of different subassemblies being on your workbench at
the same time.
The component groups are inspected and repaired from
the converter housing side.
As much as possible, complete the inspection, repair
and reassembly before proceeding to the nex t
component group. If a component group cannot be
reassembled because parts are being ordered, be sure
to keep all parts of that group in separate container
while proceeding with disassembly, inspection, repair
and reassembly of other component groups.
Recommended ATF type DEXRON III.
General Cleaning Notes:
1. All disassembled parts should be washed clean and
any fluid passages and holes should be blown
through with compressed air.
2. When using compressed air to dry parts, always aim
away from yourself to prevent accidentally spraying
automatic transmission fluid in your face.
3. The recommended automatic transmission fluid
should be used for cleaning.
Parts Arrangement:
1. After cleaning, the parts should be arranged in
proper order to allow performing inspection, repairs,
and reassembly with efficiency.
2. When disassembling a valve body, be sure to keep
each valve together with the corresponding spring.
3. New brakes and clutches that are to be used for
replacement must be soaked in transmission fluid
for at least thirty minutes before assembly.
General Assembly:
1. All oil seal rings, clutch discs, clutch plates, rotating
parts, and sliding surfaces should be coated with
transmission fluid prior to reassembly.
2. All gaskets and rubber O-ring should be replaced.
3. Make sure that the ends of a snap ring are not
aligned with one of the cutouts and are installed in
the groove correctly.
4. If a worn bushing is to be replaced, the
subassembly containing that bushing must be
replaced.
5. Check thrust bearings and races for wear or
damage. Replace if necessary.
6. Use petroleum jelly or vaseline to keep parts in
place.

7A2-6 DIAGNOSIS (JR405E)
BASIC TROUBLE SHOOTING

Transmission fluid pressure together with clutch and brake friction and other important transmission functions are
controlled by electrical signal from the Transmission Control Module (TCM).
Random diagnosis can produce inaccurate and misleading indications. It is important that diagnosing procedure be
carried out systematically.
Carefully follow the sequence outlined below to diagnose automatic transmission assembly.




Verify Customer Complain
Preliminary Check
(Visual Check/Test Drive)
Compare to Same Model
(If Available)
Check Service Bulletin
DTC Check
(Self-diagnosis/Tech 2)
Go to Symptom Diagnosis
Stall Test
Line Pressure Test
Transmission Overhaul
Repair & Verify Fix
Transmission Overhaul
Transmission Overhaul
Go to DTC Chart
Go to Intermittent Diagnosis NG
Follow the instructions
NG
No Instruction
NG
OK
NO DTC
Not Solved
OK
OK
Follow the Bulletin
(Once Clear Memory) Restored
Not Stored
Use Service Programming
System (SPS)
Not Solved

7A3-2 ON-VEHICLE SERVICE (JR405E)
DESCRIPTION
Before performing on-vehicle service on the automatic
transmission, check that the engine idling speed and
general engine condition are normal.



AUTOMATIC TRANSMISSION FLUID (ATF)
Inspect
Remove the transmission dipstick to check the condition
of the ATF.
Clean the dipstick and look for gum or varnish.
Gum or varnish indicate scorching of the clutch band
and other parts.
The transmission control module, the transmission unit,
and the vehicle must be carefully checked if gum or
varnish is present.




ATF LEVEL
Inspect
Hot Level
1. Warm up the engine and the transmission by driving
the vehicle on the road so that the temperature
reaches around 80
C (176
F).
Do not turn the engine off.
2. Park the vehicle on a level surface.
3. Apply the parking brake firmly.
4. Let the engine run at idle.
Move the select lever slowly through all the gea
r
ranges.
Stop in each gear range just long enough for the
transmission to engage.
5. Return the select lever to either “P” or “N”.
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6. Remove the ATF level dipstick.
7. Wipe the dipstick clean with a paper towel.
8. Reinsert the dipstick and wait several seconds.
9. Remove the dipstick.
The ATF level should be inside the “H” range on the
dipstick.
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If the ATF level is below the “H” range, ATF must be
added.

ON-VEHICLE SERVICE (JR405E) 7A3-19
Install or Connect
1. Align the manual valve and the manual plate of the
transmission case.
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2. Install the control valve assembly and tighten the 12
fixing bolts to the specified torque.

Number of bolts Length Color
10 (A) 40 mm (1.57 in) Gold
2 (B) 30 mm (1.18 in) Gold

Bolt torque : 8 N·m (69 lb·in)
3. Connect the 2 harness connectors.
4. If removed, install the oil strainer.
Refer to “Solenoids, Oil Pressure Switch and Oil
Temperature Sensor” previously in this section.
5. Install the new gasket and oil pan.
Bolt torque : 8 N·m (69 lb·in)
6. Fill the fluid.
Refer to “ATF CHANGE” in this section.
7. Connect the negative battery cable.
8. Remove the wheel blocks.

FLUSHING THE TRANSMISSION FLUID COOLER AND LINE
The fluid cooler and lines may be flushed under the
following condition. This will help prevent more trouble
after the transmission is repaired.
1. When the abnormal amount of debris are found.
2. When the abnormal wear or chips on gears and
shafts are found while overhauling.
3. When the abnormal clutch facing wear and oil
contamination are found.

Procedures
1. Block the wheels.
2. Disconnect negative battery cable.
3. Raise vehicle and support with suitable safety
stands.
4. Disconnect fluid cooler lines at transmission case
and fluid cooler.
5. Flush and back-flush the fluid cooler and lines using
solvent and compressed air.
Note:
DO NOT exceed 197 kPa (29 psi) air pressure or
damage may result to oil cooler.

6. Remove all remaining solvent from the system with
compressed air.
7. Flush the cooling system again with Automatic
Transmission Fluid (ATF).
After the final flush, connect all lines.
Cooler line joint connector torque :
44 N·m (33 lb·ft)
8. Replenish ATF
9. Start engine to test the system for the free flow o
f
fluid. If the flow is restricted, the cooler assembly o
r
lines must be replaced.
Repeated cleaning and flushing may not remove all
debris from the fluid cooler circuit.
Move the select lever through the various ranges and
return to neutral.
Check for fluid level.
If the fluid level is below the specified range, ATF
must be added.
10. Connect negative battery cable.
11. Remove safety stands.
12. Remove wheel blocks.