Circuit/System Testing
- Operate the vehicle in D.
- Using the scan tool record the gear ratio while accelerating in 4th gear. The gear ratio should be within 1.04:1-1.56:1.
- If the 4th gear ratio is 1.00:1, inspect and repair the control valve body assembly for the following conditions.
Refer to CONTROL VALVE BODY ASSEMBLY DISASSEMBLE .
- Stuck 2-3, 3-4 shift solenoid valve assembly
- Stuck M2 shift valve
If the conditions test normal, replace the control valve body assembly, Refer to CONTROL VALVE BODY REPLACEMENT procedure.
- If the 4th gear ratio is not within the specified range and is not 1.00:1, continue to step 3.
- Observe the scan tool Transmission OSS parameter while driving the vehicle. The reading should correspond to a known properly functioning OSS.
- If the OSS is malfunctioning, replace the Transmission Output Speed Sensor (OSS). Refer to the OUTPUT SPEED SENSOR REPLACEMENT procedure.
- Stop the vehicle, apply the parking brake, engine at idle, select P (park) using the Shift Control.
- Observe the scan tool Transmission ISS parameter. The reading should be within 400-800 RPM.
- If the ISS parameter is not within the specified range, replace the Transmission Input Speed Sensor (ISS).
Refer to the INPUT SPEED SENSOR REPLACEMENT procedure.
- Ignition ON, engine OFF, command shift solenoid 1 ON and OFF with a scan tool. The solenoid should click when commanded ON.
- If the solenoid does not click, replace the 1st shift solenoid valve assembly. Refer to CONTROL VALVE BODY ASSEMBLY DISASSEMBLE .
- Command shift solenoid 3 ON and OFF with a scan tool. The solenoid should click when commanded ON.
- If the solenoid does not click, replace the 1-2, 2-3, reverse shift solenoid valve assembly. Refer to CONTROL VALVE BODY ASSEMBLY DISASSEMBLE .
- Perform a line pressure test. Refer to LINE PRESSURE CHECK procedure.
- Remove the control valve body cover. Refer to CONTROL VALVE BODY COVER REMOVAL procedure.
- Inspect the inside of the control valve body cover for excessive sediment. There should not be excessive sediment.
- If excessive sediment is found inspect and replace as necessary the 4-5 clutch and forward clutch. Refer to 4-5 CLUTCH DRUM ASSEMBLY ASSEMBLE and FORWARD AND DIRECT CLUTCH ASSEMBLY ASSEMBLE procedures.
- Inspect the control valve body assembly for the following conditions. Refer to CONTROL VALVE REAR BODY DISASSEMBLE and MIDDLE CONTROL VALVE BODY DISASSEMBLE . The conditions should not be found.
- Stuck U1 shift valve
- Stuck M1 shift valve
- Stuck U2 shift valve
- Stuck shift pressure relay valve
- Stuck neutral relay valve
- Stuck line pressure control solenoid valve assembly
If any of the above conditions are found, replace the valve body assembly. Refer to CONTROL VALVE BODY REPLACEMENT procedure.
- Verify that the control valve body has been serviced within the past 3 months.
- If the control valve body has not been serviced, replace the control valve body assembly. Refer to CONTROL VALVE BODY REPLACEMENT .
- If all circuits and components test normal, replace the transmission.