NO.24 SHIFT CONCERN: HARSH 3–4 SHIFT[LA4AX-EL (CD4E)]

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24

Shift concern: harsh 3–4 shift

POSSIBLE CAUSE

•  Powertrain control system malfunction

•  Control valve body malfunction

•  Oil pump malfunction

•  2/4 band and servo component malfunction

•  Coasting clutch component malfunction

•  Direct clutch component malfunction

•  Transaxle case malfunction

24	Shift concern: harsh 3–4 shift
POSSIBLE CAUSE	• Powertrain control system malfunction • Control valve body malfunction • Oil pump malfunction • 2/4 band and servo component malfunction • Coasting clutch 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 range (TR) switch ― Vehicle speedometer sensor (VSS) ― 3-2 timing/coasting clutch solenoid (3-2T/CCS) ― Transaxle fluid temperature (TFT) sensor ― Turbine shaft speed (TSS) sensor ― Throttle position (TP) sensor ― Mass air flow (MAF) sensor ― TCC solenoid	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 (also harsh 1-2 and 2-3 shifts), 3-2 control valve, 2/4 accumulator valve, coasting clutch valve are stuck, damaged, or misassembled ― Hydraulic passages are damaged ― Separator plates are damaged or blocked	Yes	Service if necessary
2		No	Go to the next step
3	Oil pump • Do any of the following malfunctions exist? ― Bolts are not tightened to the specification ― Gasket is damaged ― Porosity/cross leakage ― Coasting clutch Teflon seals are damaged	Yes	Service if necessary
3		No	Go to the next step
4	2/4 band and servo component • Do any of the following malfunctions exist? ― 2/4 band and/or reverse clutch drum component are damaged, worn, or misassembled ― Servo piston or cover is damaged or leaking ― Springs are damaged	Yes	Service if necessary
4		No	Go to the next step
5	Coasting clutch component • Do any of the following malfunctions exist? ― Piston or seals are damaged or missing ― Friction is damaged or worn ― Inspect the ball for not functioning	Yes	Service if necessary
5		No	Go to the next step
6	Direct clutch component • Do any of the following malfunctions exist? ― Piston or seals are damaged or missing ― Inspect the ball for damage, missing, or leaking ― Return spring is damaged ― Friction elements are damaged ― F/C/D clutch cylinder splines are damaged	Yes	Service if necessary
6		No	Go to the next step
7	Transaxle Case • Is the band anchor damaged?	Yes	Service if necessary
7	Transaxle Case • Is the band anchor damaged?	No	The malfunction is not in the automatic transaxle Go to the engine symptom troubleshooting (See ENGINE SYMPTOM TROUBLESHOOTING[AJ (3.0L Duratec)].)
8	• 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.