Neon Transmission Grinding & Warning Lights w/Bad Shifts

Had the same symptoms on a 2008 Chrysler Sebring last summer. The grinding and emergency mode turned out to be a failed oil cooler causing transmission fluid to mix with radiator coolant. The pressure sensor was reporting incorrect readings, causing the transmission control unit to trigger limp mode. The coolant leak wasnt visible at first since it was internal contamination. A transmission fluid analysis showed coolant particles, confirming the diagnosis. This required replacing the oil cooler assembly and flushing both the transmission and cooling system completely. The cooling fan also needed replacement since it was cycling incorrectly due to the compromised sensor data. This is definitely a serious issue that needs immediate attention, continuing to drive risks complete transmission failure. The contaminated fluid damages internal components rapidly. Would strongly recommend getting a second opinion from a transmission specialist who can properly diagnose the root cause. The symptoms match classic signs of oil cooler failure in these models. Have them check the radiator coolant color and pressure test both systems before replacing parts.

Thanks for sharing your experience with the oil cooler failure and radiator repair. Just curious, do you remember what the total repair cost was? Mine seems very similar to what you described with the transmission acting up and coolant leak issues. Would also like to know if everything has been running smoothly since the fix. I heard these cooling system problems can sometimes come back even after repairs. Have you noticed any pressure sensor warnings or transmission issues popping up again?

Just wanted to update on the repair costs and results. The main issue was indeed a faulty pressure sensor giving wrong readings to the transmission control unit. After the mechanic found the loose connection and fixed the wiring harness for 95€, the cooling system has been working perfectly. The pressure gauge now shows correct readings and the transmission shifts smoothly, no more grinding or emergency mode problems. Not a single warning light has appeared in the months since the repair. The cooling fan cycles normally now that it gets accurate sensor data. Really glad it turned out to be just a connection issue rather than needing a full oil cooler replacement like initially feared. No coolant leaks or transmission problems have returned. This experience shows why getting a proper diagnosis is crucial, what seemed like a major transmission issue was solved by fixing a simple sensor connection. Much better outcome than unnecessarily replacing expensive components.

After reading about your experience, I finally took my car to a different transmission specialist last week. The leak detection test revealed exactly what you described, the oil cooler was leaking and mixing fluids. Total repair came to 850€ including parts and labor for the cooler replacement and system flush. The mechanic showed me how the radiator coolant had turned brownish from the contamination. They also found the transmission pressure sensor was damaged from the fluid mixing. Replacing both components fixed the grinding and emergency mode issues completely. Been driving for about a week now and the transmission shifts perfectly again. The cooling fan runs properly and engine temperature stays normal. Such a relief to have it properly diagnosed and fixed instead of throwing parts at the problem like the first shop suggested. Really appreciate the advice about getting a second opinion from a specialist. Saved me from potentially destroying the transmission by continuing to drive with contaminated fluid.