Isuzu KB P190. Manual - part 1024

ON-VEHICLE SERVICE (AW30–40LE)  7A3-11 

Measure Time Lag 

  1. Fully apply the parking brake. 

  2. Start the engine. 

Check idling speed (A/C OFF). 

  3. Operate the select lever from “N" to “D" position. 

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 

•  First and Reverse 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: 5-8840-0093-0 

NOTE:  Perform the test at normal operating fluid 
temperature (50 – 80

°C or 122 – 176°F). 

 
 

 

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

Measure Line Pressure 

  1. Fully apply the parking brake and chock the four

wheels. 

  2. Start the engine and check idling rpm. 

  3. Select into “D" position, step down strongly on the

brake pedal with your left foot and while
manipulating the accelerator pedal with the right
foot, measure the line pressures at the engine
speeds specified in the table. 

 4. 

In the same manner, perform the test in “R"
position. 

 

  

Line pressure kPa (kg/cm

2

/psi) 

Engine 

speed 

“D" position 

“R" position 

Idling 

349 – 408 

(3.6 – 4.2 /51 – 59) 

577 – 675 

(5.9 – 6.9/84 – 98) 

Stall 

1,206 – 1,353 

(12.3–13.8/175–196)

1,646 – 1,979 

(16.8–20.2/239–287)

 

Evaluation 

  1. If the measured values at all positions are higher

than specified: 

•  Pressure control solenoid defective 

•  Primary regulator valve defective 

  2. If the measured values at all positions are lower

than specified: 

•  Primary regulator valve defective 

•  Oil pump defective 

•  Pressure control solenoid defective 

  3. If pressure is low in “D" position only: 

•  “D" position circuit fluid leakage 

  4. If pressure is low in “R" position only: 

•  “R" position circuit fluid leakage 

Road Test 

NOTE:  Perform the test at normal operating fluid 
temperature (50 – 80

°C or 122 – 176°F). 

“D" Position Test in “NORMAL", and
“POWER" Pattern 

Select into the “D" position and hold the accelerator
pedal constant at the 50% and 100% throttle valve
opening positions. 

Push in one of the pattern selector buttons and check
the following: 

 

 

1. 1–2, 2–3, 3–OD and lock-up, upshifts should take 

place, and shift points should conform to those 
shown in the automatic shift diagram. 

 

 

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ON-VEHICLE SERVICE (AW30–40LE)  7A3-13 

Evaluation 

i.  If there is no 1

→2 upshift: 

•  Solenoid S2 is stuck 

•  1–2 shift valve is stuck 

ii.  If there is no 2

→3 upshift: 

•  Solenoid S1 is stuck 

•  2–3 shift valve is stuck 

iii. If there is no 3

→OD upshift (throttle valve opening

1/2): 

•  Solenoid S2 is stuck 

•  3–OD shift valve is stuck 

iv. If the shift point is defective: 

Refer to TROUBLESHOOTING CHART in this 
section. 

v.  If the lock-up is defective: 

Refer to TROUBLESHOOTING CHART in this 
section. 

2. In the same manner, check the shock and slip at the

1

→2, 2→3 and 3→OD upshifts. 

NOTE:  Drive the vehicle on level ground. 

Evaluation 

If the shock is excessive: 

Refer to TROUBLESHOOTING CHART in this section.

3. Run at “D" position lock-up or OD gear and check for

abnormal noise and vibration. 

NOTE:  The check for the cause of abnormal noise and 
vibration must be made with extreme care as it could
also be due to loss of balance in the propeller shaft,
differential, the torque converter, etc. or insufficient
bending, rigidity, etc. in the power train. 

 

 
 

 

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4. While running in “D" position, 2nd, 3rd gears and 

OD, check to see that the possible kick-down 
vehicle speed limits for 2

→1, 3→1, 3→2, OD→3 

and OD

→2 kick-downs conform to those indicated 

on the automatic shift diagram. 

 

 

 

 

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5. Check for abnormal shock and slip at kick-down. 

6. While running in “D" position, OD gear or “lock-up", 

shift to “2" and “L" positions and check the engine 
braking effect at each of these positions. 

 

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

Evaluation 

i. If there is no engine braking effect in the “2"

position: 

•  Second coast (No.1) brake is defective. 

 

ii. If there is no engine braking effect in the “L"

position: 

•  First and reverse (No.3) brake is defective. 

 

 
 
 
 

 

 

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iii. Also check to see that downshift is made from 3 to 

2 or from OD to 3 and then to 2 immediately and
that 2

→1 downshift point is within the limits shown

in the diagram when tested by releasing the
accelerator pedal and operaing into “L" position
while driving in the third gear or in overdrive. 

 

 
 

 

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“2" Position Test 

Select into “2" position and, while driving with the 
accelerator pedal held constantly at the specified point
(throttle valve opening 50% and 100%), push in one of
the pattern selectors and check on the following points.

  1. At each of the above throttle openings, check to see 

that the 1

→2 upshift takes place and that the shift 

points conform to those shown on the automatic 
shift diagram. 

NOTE:  There is no OD and no lock-up in the “2" 
position. 

 

 

 

 

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  2. While running in the “2" position and 2nd gear, 

release the accelerator pedal and check the 
engine's braking effect. 

 3. Check for 2

→1 downshift and abnormal noise at 

acceleration and deceleration, and for shock at 
upshift and downshift. 

 

 
 
 
 

 

 

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