Stall Speed Test
WARNING:
Apply the parking brake firmly while carrying out each Stall Speed Test.
CAUTION:
Carry out Line Pressure Test prior to carrying out stall test. If the line pressure is low at stall, do not carry out Stall Speed Test or further transmission damage will occur.
The Stall Speed Test checks:
- torque converter clutch operation and installation.
- holding ability of the forward clutch.
- reverse clutch (the low-reverse bands).
- planetary one-way clutch.
- engine driveability.
Conduct this test with the engine coolant and transmission fluid at correct levels and at normal operating temperature.
Apply the parking brake firmly for each Stall Speed Test.
- Find the specified stall rpm for the vehicle; refer to the STALL SPEED DIAGNOSIS . Use a grease pencil to mark the rpm on the dial of a tachometer.STALL SPEED
Engine Stall Speed rpm 4.6L 2,031-2,374 4.6L (with Handling Package) 2,372-2,808 - Connect a tachometer to the engine.
- In each of the following ranges R, (D), 2, 1 press the accelerator pedal to the floor and hold it just long enough to let the engine get to wide open throttle (WOT). While making this test, do not hold the throttle open for more than 5 seconds at a time.
- Note the results in each range.
- After each range, move the shift control selector lever to NEUTRAL and run the engine at 1,000 rpm for about 15 seconds to cool the torque converter before making the next test.
- Refer to STALL SPEED DIAGNOSIS for corrective actions.
NOTE:
If the rpm recorded by the tachometer exceeds the maximum limits, release the accelerator pedal immediately because clutch or band slippage is indicated.
STALL SPEED DIAGNOSIS
| Selector Position | Stall Speeds High | Stall Speeds Low |
|---|---|---|
| (D) | Planetary One-Way Clutch | |
| (D), 2 and 1 | Forward Clutch or Intermediate Clutch | |
| R, (D),2, 1 | Carry Out Pressure Test | Torque Converter Stator One-Way Clutch or Engine Driveability Concerns |
| R | Reverse Clutch or Low Reverse Band or Servo |