Automatic Transmission - Mechanical System Tests - Toyota HILUX 1993 Repair Manual

Mechanical System Tests
STALL TEST
The objective of this test is to check the overall performance of the transmission and engine by measuring
the maximum engine speeds in the D and R positions.
NOTICE:
Perform the test at normal operating fluid temperature (50–80SC or 122–176SF).
Do not continuously run this test longer than 5 seconds.
To ensure safety, conduct this test in a wide, clear, level area, which provides good traction.
MEASURE STALL SPEED
(a) Check the four wheels and fully apply the parking brake.
(b) Mount an engine tachometer.
(c) Keep your left foot pressed firmly on the brake pedal, and start the engine.
(d) Shift into the D position. Step all the way down on the accelerator pedal with your right foot.
Quickly read the highest engine RPM at this time.
Stall speed: 1,900 150 RPM
(e) Perform the same test in the R position.
EVALUATION
(a) If the engine speed is the same for both positions but lower than specified value:
Engine output may be insufficient
Stator one–way clutch is not operating properly
HINT: If more than 600 RPM below the specified value, the torque converter clutch could be faulty.
(b) If the stall speed at the D position is higher than specified:
Line pressure too low
Front clutch slipping
No.2 one–way clutch not operating properly
O/D one–way clutch not operating properly
(c) If the stall speed at the R position is higher than specified:
Line pressure too low
Rear clutch slipping
No.3 brake slipping
O/D one–way clutch not operating properly
(d) If the stall speed in both R and D positions are higher than specified:
Line pressure too low
Improper fluid level
O/D one–way clutch not operating properly
AUTOMATIC TRANSMISSION – Troubleshooting (Mechanical System Tests)
AT–20