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Home >> Mercury Truck >> 2009 >> Mountaineer AWD V8-4.6L >> Repair and Diagnosis >> Transmission and Drivetrain >> Automatic Transmission/Transaxle >> Testing and Inspection >> Component Tests and General Diagnostics >> 5R55S >> Special Testing Procedures >> Stall Speed Test

Stall Speed Test




Stall Speed Test

This test checks operation of the following items:

- Torque Converter Clutch (TCC)
- Forward clutch
- Low One-Way Clutch (OWC) assembly
- Engine driveability concerns
- O/D OWC assembly

WARNING: Block all wheels, set the parking brake and firmly apply the service brake to reduce the risk of vehicle movement during this procedure. Failure to follow these instructions may result in serious personal injury.

NOTICE: Always perform the Line Pressure Test procedures prior to performing the Stall Speed Test. If line pressure is low at stall, do not perform the Stall Speed Test or further transmission damage will occur.

NOTICE: After testing each of the following ranges D, 3, 2, 1 and R, move the selector lever to NEUTRAL and run the engine at 1,000 rpm for about 15 seconds to allow the torque converter to cool before testing the next range. Failure to follow this instruction may result in transmission damage.

NOTICE: Do not maintain Wide Open Throttle (WOT) in any range for more than 5 seconds. Failure to follow this instruction may result in transmission damage.

NOTICE: If the engine rpm recorded by the scan tool exceeds maximum specified rpm, release the accelerator pedal immediately. Failure to follow this instruction may result in transmission damage. Clutch or band slippage is indicated.

NOTE: The Stall Speed Test should be performed with the engine and transmission at normal operating temperatures.

NOTE: Prolonged use of this procedure may set DTC P0712 or P1783. After performing the Stall Speed Test, run the On-Board Diagnostic (OBD) Test and clear the DTCs.

1. Connect a scan tool to the vehicle.

2. Press the accelerator pedal, WOT in each range. Record rpm reached in each range. Stall speeds should be as follows:

Stall Speed Chart:





If the stall speeds were too high, refer to the following Stall Speed Diagnosis Chart. If the stall speeds were too low, first check the engine idle speed. If engine idle is OK, remove the transmission and replace the torque converter.

Stall Speed Diagnosis Chart:




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