Special Testing Procedures

Special Testing Procedures





The special tests are designed to aid the technician in diagnosing the hydraulic and mechanical portions of the transmission.

Line Pressure Test










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: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If line pressure is low, do not carry out the Stall Speed Test or additional transmission damage will occur. Do not maintain Wide Open Throttle (WOT) in any transmission range for more than 5 seconds or transmission damage may occur.

NOTE: Certain input sensor failures may cause high line pressure and Failure Mode Effect Management actions. Make sure that the On-Board Diagnostic (OBD) test and electrical repairs have been carried out or test results may be incorrect.

This test verifies the line pressure is within specifications.

1. Connect the Transmission Fluid Pressure Gauge to the line pressure tap.

2. Start the engine and check the line pressures at idle speeds with the transmission in each gear range. Refer to the following Pressure Charts to determine if the line pressure is within specification.

3. Check line pressure at WOT (Wide Open Throttle) stall speed with the selector lever in all gear ranges. Slowly press the accelerator pedal to WOT (Wide Open Throttle) and record the pressure reading. After recording the pressure reading, slowly release the accelerator pedal until closed throttle is obtained (idle). Refer to the following Pressure Charts to determine if the line pressure is within specification.

4. If pressure is not within specification, refer to the Line Pressure Diagnostic Chart for further diagnosis.

5. When the line pressure test is completed, install the line pressure tap plug.
- Tighten to 12 Nm (106 lb-in).


Pressure Chart A

NOTE: Actual and commanded pressures vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.





a Commanded pressure as viewed on diagnostic equipment.

Pressure Chart B

NOTE: Actual and commanded pressures vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.





a Commanded pressure as viewed on diagnostic equipment.

Pressure Chart C

NOTE: Actual and commanded pressures vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.





a Commanded pressure as viewed on diagnostic equipment.

b Shift solenoid pressure control D commanded pressure as viewed on diagnostic equipment will be zero. The manual valve controls pressure to the direct clutch in the R detent position.

Pressure Chart D

NOTE: Actual and commanded pressures vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.





a Commanded pressure as viewed on diagnostic equipment.

Line Pressure Diagnostic Chart






Stall Speed Test

NOTICE: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If line pressure is low, do not carry out the stall test or additional transmission damage will occur. Do not maintain Wide Open Throttle (WOT) in any gear range for more than 5 seconds.

NOTE: After testing each of the ranges, move the selector lever into the NEUTRAL position and run the engine at 1,000 rpm for about 15 seconds to allow the torque converter to cool off before continuing onto the next range.

NOTE: If the engine speed recorded by the tachometer exceeds maximum specified rpm, release the accelerator pedal immediately.

NOTE: Only perform the Stall Speed Test with the engine and transmission at normal operating temperatures.

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

The Stall Speed Test checks the operation of the following items:

- Torque converter reactor One-Way Clutch (OWC)

- Forward clutch

- Low OWC (One-Way Clutch)

- Overdrive OWC (One-Way Clutch)

- Engine driveability concerns

1. Connect a scan tool.

2. Press the accelerator pedal to WOT (Wide Open Throttle) in each range. Record the rpm reached in each range. Stall speeds should be in the appropriate range.

Stall Speed Chart






Stall Speed Diagnosis Chart






Air Pressure Tests

Air Pressure Test Port Locations










A no-drive condition can exist, even with correct transmission fluid pressure, because of inoperative clutches or bands. See the Clutch, Solenoid, Application Charts, refer to Specifications to determine the appropriate elements. A clutch concern can be located through a series of checks by substituting air pressure for transmission fluid pressure to determine the location of the concern.

Example: When the selector lever is in a forward gear range, a no-drive condition may be caused by an inoperative forward clutch.

1. Drain the transmission fluid. Remove the transmission fluid pan.

2. Remove the transmission filter and seal assembly, the solenoid body and solenoid-to-case gasket.

3. Install the Air Test Plate along with the Transmission Test Plate Screw Set.
- Tighten to 10 Nm (89 lb-in).

4. Locate the inoperative clutches by applying air pressure into the appropriate clutch port. See the Air Pressure Test Port Locations illustration for clutch port locations.

5. Apply 276 kPa (40 psi) of air pressure to the appropriate clutch port. A dull thud may be heard or movement felt when a clutch piston is applied. If the clutch seals or check ball are leaking, a hissing sound may be heard.

6. If the clutches fail to operate during the air check:
- inspect the transmission fluid passages in the case.

- the piston seals are not seated, not installed or are damaged.

- plugged feed holes for clutch apply in the case and/or clutch cylinder.

- damaged piston and/or clutch cylinder.

7. Repair as required and recheck.

8. Reinstall all components.