Owner's Problem Description
The owner of a 2001 Chrysler Sebring reports a significant problem with the transmission, specifically experiencing a bind-up in 3rd gear after driving for about a mile. Previous repairs include rebuilding the transaxle with a remanufactured torque converter and pump, but after a short distance, the vehicle burned the 2nd clutches. The owner has replaced the PCM, MLP sensor, valve body, and solenoids, yet the issue persists, becoming worse the longer the vehicle is driven. The only workaround is to shift to D2 to prevent further damage.
Professional Technical Analysis
The 2001 Chrysler Sebring, equipped with a Mitsubishi F4A51-2 transmission and approximately 150,000 miles, exhibits a persistent bind-up in 3rd gear shortly after starting. The transaxle was initially rebuilt, including a remanufactured torque converter and pump, but the vehicle burned the 2nd clutches after only 5 miles of driving, indicating potential issues with clutch engagement or hydraulic pressure management. Post-repair efforts included replacing the Powertrain Control Module (PCM), Manual Lever Position (MLP) sensor, valve body, and solenoids, with all wiring integrity confirmed through testing. Despite these measures, the transmission still fails to keep the second solenoid activated, leading to the application of the 2nd clutch while in 3rd gear, causing premature wear and potential clutch failure. The bind-up becomes progressively worse with extended driving, highlighting a need for further diagnostic evaluation of solenoid operation and hydraulic control systems. Current assessments suggest that the PCM is not grounding the 2nd solenoid adequately, which is crucial for proper clutch application and gear shifting. The absence of trouble codes further complicates the diagnosis, necessitating a detailed investigation into the transmission control parameters and electrical signals governing solenoid function.
Possible Causes
Most common causes (ordered by frequency):
- PCM Grounding Issue: The PCM may not be grounding the second solenoid effectively, preventing the clutch from disengaging properly. Testing should confirm the PCM's output to the solenoid during operation, with expected resistance values of 10-20 ohms across the solenoid terminals. If the PCM fails to provide consistent grounding, this could lead to improper clutch engagement and bind-up conditions in higher gears. Additionally, the wiring integrity should be monitored, as intermittent connections can cause erratic solenoid behavior. - No trouble codes stored, intermittent solenoid engagement, resistance measurements outside expected range.
- Hydraulic Control Issues: The hydraulic system may be experiencing a blockage or failure within the valve body, preventing proper fluid flow to the second solenoid. This can lead to improper clutch application and binding in 3rd gear. Pressure tests should be conducted to confirm the hydraulic pressure at the valve body, with expected ranges of 60-80 PSI during operation. Any deviation from these values may indicate a blockage or internal failure requiring further inspection. - Inconsistent clutch engagement, abnormal hydraulic pressure readings, signs of fluid contamination.
- Electrical Connector Malfunctions: Corrosion or damage to the wiring harness connecting the PCM and solenoids may result in poor electrical connections. This could prevent the solenoid from receiving adequate voltage or ground, leading to incomplete clutch application. Inspection of the wiring harness for signs of wear, corrosion, or loose connections is essential. Voltage drop tests should show no more than 0.5V across the connector under load. - Visual inspection reveals corrosion on connectors, voltage drop testing indicates poor connection, intermittent solenoid activation.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial Scan and Data Retrieval: Begin by utilizing the GeekOBD APP to scan the vehicle for any stored trouble codes, even if none are currently present. This will help confirm the absence of faults and provide a baseline for further diagnostics. The APP's live data feature can also be helpful in monitoring solenoid activation and PCM outputs during a test drive, allowing for real-time observations of the transmission's behavior.
- STEP 2 - Electrical Testing: Perform electrical testing on the solenoid circuit using a multimeter, checking for proper voltage supply and ground at the solenoid terminals while the engine is running. The ideal voltage should be between 12-14V when the solenoid is activated. Additionally, measure the resistance of the solenoid coils to ensure they are within specification (expected 10-20 ohms). Any inconsistencies may indicate a fault in the wiring or solenoids.
- STEP 3 - Hydraulic Pressure Testing: Conduct hydraulic pressure testing at the valve body to gauge the fluid pressure during operation. The expected pressure range is between 60-80 PSI. A gauge should be connected to the test port on the valve body to monitor pressure fluctuations while the vehicle is driven. Any significant drops in pressure may indicate internal blockages or valve body malfunctions.
- STEP 4 - Road Testing and Observation: Perform controlled road tests while using the GeekOBD APP to monitor real-time data. Focus on the transmission's shifting behavior, solenoid activation, and any abnormal noises or sensations while driving. Document any parameter deviations and correlate them with the symptoms experienced, especially after the vehicle has been driven for a mile or more.
