NO.18 SHIFT CONCERN: SOFT/SLIPPING 3–4 SHIFT[LA4AX-EL (CD4E)]

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18

Shift concern: soft/slipping 3–4 shift

POSSIBLE CAUSE

•  Powertrain control system malfunction

•  Control valve body malfunction

•  2/4 band and servo component malfunction

•  Direct clutch component malfunction

•  Transaxle case malfunction

18	Shift concern: soft/slipping 3–4 shift
POSSIBLE CAUSE	• Powertrain control system malfunction • Control valve body malfunction • 2/4 band and servo component malfunction • Direct clutch component malfunction • Transaxle case malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	Powertrain control system • Are there any malfunctions with the following? ― Electrical input/output ― Vehicle wiring harness ― PCM ― Electrical pressure control (EPC) solenoid ― Transaxle fluid temperature (TFT) sensor	Yes	Perform OBD test Perform DTC troubleshooting (See AUTOMATIC TRANSAXLE ON-BOARD DIAGNOSTIC FUNCTION[LA4AX-EL (CD4E)].)
1		No	Go to the next step
2	Control valve body • Do any of the following malfunctions exist? ― Bolts are not tightened to the specification ― Gasket leaks ― Line modulator valve, 2/4 accumulator valve plug and seal (also soft 1-2 shift), are stuck, damaged, or misassembled ― Pressure tap plate/gasket leaks ― Hydraulic passages are damaged ― Separator plates are damaged, or the orifice is blocked	Yes	Service if necessary
2		No	Go to the next step
3	2/4 band and servo component • Do any of the following malfunctions exist? ― 2/4 Band and/or reverse clutch drum component are worn, damaged, or misassembled ― Piston seals or piston bore is damaged or missing ― Servo cover or seal is damaged ― Servo rod or rod bore is damaged ― Springs are damaged	Yes	Service if necessary
3		No	Go to the next step
4	Direct clutch component (There may also be third gear slipping) • Do any of the following malfunctions exist? ― Seals are damaged or missing ― Pistons are damaged ― Inspect the check ball for damage, loss, or leakage ― Return spring is damaged ― Friction elements are damaged	Yes	Service if necessary
4		No	Go to the next step
5	Transaxle case • Do any of the following malfunctions exist? ― Band anchor is damaged ― Leakage in the servo apply and servo release	Yes	Service if necessary
5		No	The malfunction is not in the automatic transaxle Go to the engine symptom troubleshooting (See ENGINE SYMPTOM TROUBLESHOOTING[AJ (3.0L Duratec)].)
6	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. ― If the malfunction remains, inspect the related Service Information and perform repair or diagnosis. • If the vehicle is repaired, troubleshooting is completed. • If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.