Purpose/Description Of Test
A stall test is preformed to inspect the overall performance of the automatic transmission and engine assembly by measuring the stall speed in both the DRIVE and REVERSE gear ranges.
Conditions
• | Verify that the automatic transmission fluid (ATF) temperature is between 70-80°C (156-176°F). |
• | All additional electrical loads are OFF. |
Caution: Do not continuously run the test procedure for longer than 5 seconds because of the extreme increase in the automatic transmission fluid (ATF) temperature. Also, be sure to keep the interval
between stall tests to more than 1 minute in order to prevent damage to the automatic transmission internal components.
Procedure
- Chock all 4 wheels and fully apply the parking brake in order to prevent any vehicle movement during testing.
- Apply firm pressure to the service brake pedal with the left foot in order to apply the service brakes.
- Move the automatic transmission manual gearshift selector from the PARK position to the DRIVE position.
- Evenly press the accelerator pedal to the wide-open throttle (WOT) position with the right foot.
- Record the maximum engine RPM noted within 5 seconds of achieving the WOT position, and then return to the closed throttle position. Return the gear selector to the PARK position.
- Wait 1 minute before proceeding to the next portion of the test procedure.
- Move the automatic transmission manual gearshift selector from the PARK position to the REVERSE position.
- Evenly press the accelerator pedal to the wide-open throttle (WOT) position with the right foot.
- Record the maximum engine RPM
2,545 RPM noted within 5 seconds of achieving the WOT position, and then return to the closed throttle position. Return the gear selector to the PARK position.
Stall Test Results
Result
| Possible Cause
|
Observed RPM is Lower than the specification in both drive and reverse ranges
|
• | Torque converter clutch (TCC) internal one-way clutch failure |
|
Observed RPM is higher than the specification in Drive only
|
• | Line pressure is below specifications |
• | Forward clutch (C1) concern |
|
Observed RPM is higher than the specification in Reverse only
|
• | Line pressure is below specifications |
• | Reverse gear clutch (C2) slipping |
• | 1st and reverse clutch (B2) slipping |
|
Observed RPM is higher than the specification in both Drive and Reverse ranges
|
• | Line pressure is below specifications |
• | Coast Clutch (C3) failure |
|