2004 ISUZU TF SERIES low oil pressure

7A2-142 DIAGNOSIS (JR405E)
1. Oil Cooler Out
2. R Range Line Pressure Detection Port
(Low & Reverse Brake Pressure Detection Port)
3. D, 3, 2 & L Range Line Pressure Detection Port
(Low Clutch Pressure Detection Port)
4. Oil Cooler In

4. If the line pressure is lower than standard value at
idling in L and R ranges.


ATF leaking from low and reverse brake hydraulic
circuit.
5. If the line pressure is higher than standard value at
idling in all ranges.

Throttle opening signal reception error.

Faulty oil temperature sensor.

Faulty operation of low clutch solenoid.

Sticking pilot valve.

Sticking pressure regulator valve or plug.
6. If the line pressure is lower than standard value at stall
speed in all ranges.

Throttle opening signal reception error.

Faulty operation of line pressure solenoid.

Faulty operation of low clutch solenoid.

Sticking pilot valve.

Sticking pressure regulator valve or plug.

DIAGNOSIS (JR405E) 7A2-143
TIME LAG TEST
Procedure
1. Chock the four wheels.
2. Warm up the engine.
3. Apply the parking brake.
4. Step on the foot brake fully.
5. Set the select lever from N to D or N to R range.
6. Record the time from when moving the select button until
feeling shock.

Time Lag
Standard:
N to D Range: Below 0.7 Seconds
N to R Range: Below 1.2 Seconds

Evaluation
1. If the time lag is out of standard value when shifting N
to D range.

Forward range line pressure is low.

Slip of low clutch.

Slip of low one-way clutch.

Trouble in control valve body (faulty operation, sticking,
clogged oil passage).

Faulty low clutch duty solenoid operation.

Shortage or faulty quality of ATF.
2. If the time lag is out of standard value when shifting N
to R range.

Reverse range line pressure is low.

Slip of low & reverse brake.

Slip of reverse clutch.

Trouble in control valve body (faulty operation, sticking,
clogged oil passage).

Faulty low & reverse brake duty solenoid operation.

Shortage or faulty quality of ATF.

DIAGNOSIS (JR405E) 7A2-157
No. Wire
Color Pin Name Input /
OutputConnected toMeasurement
Item Measurement
Condition StandardInspection
Point at
Trouble
At other than
R range, L
range 1st gear More than 10
V Related
harness
B12 YEL Low & Reverse Brake Pressure Switch InputLow & reverse
brake pressure
switch Voltage
At R range, L
range 1st gear Less than 2VPressure
switch
Related
harness
B13 YEL/
RED Vehicle Speed Sensor InputVehicle speed
sensor Voltage (Wave
form) At run in L
range in 1 st
gear 20 km/h.
Circuit tester
(+) to B13 pin,
(-) to B5 pin. Pulse
generated (At
AC range
approx. 6.8V)Vehicle
speed sensor
B14 BLU/
BLK ATF Thermo Sensor Ground - ATF thermo
sensor Continuity Normally Continuity Related
harness
B15 BLK Ground - Ground Voltage Normally Less than 2VRelated
harness
B16 - - - - - - - -
At lock-up.
Circuit tester
(+) to B17 pin,
(-) to B5 pin. Pulse
generated (At
AC range
approx. 2.2 -
9.0V) Related
harness
B17 BLK Lock-up Duty Solenoid OutputLock-up duty
solenoid Voltage (Wave
form)
At unlock-up.
Circuit tester
(+) to B17 pin,
(-) to B5 pin. Pulse
generated (At
AC range
approx. 1.0 -
2.0V) Duty solenoid
At key switch
ON 10 – 14.5V Related
harness
B18 WHT V ign (Ignition Power Supply) Input Key switch Voltage
At key switch
OFF Less than 2V Fuse
At R range 10 – 14.5V Related
harness
B19 RED/
YEL R Range Switch Input Inhibitor switch Voltage
At other than
R range Less than 2VInhibitor
switch
At other than
3rd or 4th
gear More than 10
V Related
harness
B20 WHT/
BLK High Clutch Oil Pressure Switch InputHigh clutch
pressure switch Voltage
At 3rd or 4th
gear Less than 2VPressure
switch
At L range 10 – 14.5V Related
harness
B21 PNK/
BLK L Range Switch Input Inhibitor switch Voltage
At other than
L range Less than 2VInhibitor
switch
B22 GRY/
RED Ground Return Output Shift solenoid Continuity Normally Continuity Related
harness
At N range 10 – 14.5V Related
harness
B23 VIO Line Pressure Solenoid OutputLine pressure
solenoid Voltage
At D range
stall Less than 2V Solenoid

7A3-16 ON-VEHICLE SERVICE (JR405E)
SOLENOIDS, OIL PRESSURE SWITCH AND OIL TEMPERATURE
SENSOR
244L300003
Legend
1. High clutch oil pressure switch connector
(wire color: Gray)
2. 2-4 brake oil pressure switch connector
(wire color: Brown)
3. Low and reverse brake oil pressure switch connector
(wire color: White)
4. Low and reverse brake duty solenoid connector
(wire color: Pink and White)
5. High clutch duty solenoid connector
(wire color: Green and Gray)

6. Lock-up duty solenoid connector
(wire color: Yellow and Black)
7. 2-4 brake duty solenoid connector
(wire color: Blue and Brown)
8. Low clutch duty solenoid connector
(wire color: Orange and Black)
9. Line pressure solenoid connector
(wire color: Pink)

ON-VEHICLE SERVICE (JR405E) 7A3-19
Install or Connect
1. Align the manual valve and the manual plate of the
transmission case.
43ASSY119
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.

7A4-12 UNIT REPAIR (JR405E)

06CV19

5. Solenoid
6. Oil pressure switch Remove the 6 solenoids together and the 3 oil pressure
switchs.


07CV17

7. Control valve upper body
8. Control valve lower body
9. Separation plate
Remove the 17 bolts securing the control valve uppe
r
body, the control valve lower body, and the separation
plate.


08CV16



Separate the upper body, the lower body, and the
separation plate.
NOTE:
Take care not to drop or lose the parts at the inside of the
control valve.

Inspection


Inspect the separation plate for wear and other damage.

UNIT REPAIR (JR405E) 7A4-15
244L300003
Legend
1. High clutch oil pressure switch connector
(wire color: Gray)
2. 2-4 brake oil pressure switch connector
(wire color: Brown)
3. Low and reverse brake oil pressure
switch connector (wire color: White)
4. Low and reverse brake duty solenoid
connector (wire color: Pink and White)
5. High clutch duty solenoid connector
(wire color: Green and Gray)


6. Lock-up duty solenoid connector (wire
color: Yellow and Black)
7. 2-4 brake duty solenoid connector (wire
color: Blue and Brown)
8. Low clutch duty solenoid connector (wire
color: Orange and Black)
9. Line pressure solenoid connector (wire
color: Pink)

UNIT REPAIR (JR405E) 7A4-23

CONTROL VALVE LOWER BODY

10CV11
Legend
1. Retainer plate, spring, and steel ball
2. Retainer plate, plug, spring, and
pressure regulator valve
3. Retainer plate, spring, and high clutch
accumulator
4. Retainer plate, plug, low and reverse
brake fail valve A, and spring
5. Retainer plate, plug, spring, and fail
valve
6. Retainer plate, plug, low and reverse
brake amp valve, and spring
7. Oil pressure switch
8. Oil filter
9. Solenoid
10. Line pressure solenoid
11. Lock-up solenoid

12. Harness bracket
13. Solenoid fixing plate
14. Harness assembly
15. Retainer plate, plug, spring, and 2-4
brake fail valve A
16. Retainer plate, plug, spring, and low
clutch amp valve B
17. Retainer plate, spring, and torque
converter relief valve
18. Oil strainer
19. Control valve lower body
20. Retainer plate, spring, and 2-4 brake
solenoid accumulator
21. Oil pressure switch