* Overdrive doesn't engage: This is the most obvious symptom. The transmission might shift through the gears normally up to third, but then refuse to shift into overdrive (fourth gear). You'll notice the engine RPMs staying higher than expected at highway speeds.
* Harsh or rough engagement of overdrive: Instead of a smooth shift into overdrive, you might feel a bang, clunk, or shudder when it engages.
* Slipping in overdrive: You might feel the engine revving higher than normal while maintaining a constant speed, even in overdrive. This indicates the clutch packs within the overdrive are wearing out and not gripping properly.
* Overdrive intermittently engages and disengages: This is a common symptom of a problem with the overdrive solenoid or wiring. The overdrive might work sometimes and fail other times, often depending on the temperature or load on the transmission.
* Increased engine temperature: The constant higher RPMs from overdrive malfunction can lead to increased engine strain and overheating.
* Transmission fluid issues: Check your transmission fluid. If it's low, burnt (smells burnt), or has metallic particles in it, it points towards a serious transmission problem, potentially including the overdrive.
* Check Engine Light: A malfunctioning overdrive can trigger the Check Engine Light, though the code might not specifically identify overdrive failure, but rather a more general transmission issue. You'll need a code reader to decipher what the light indicates.
Important Note: It's crucial to distinguish between overdrive problems and other transmission issues. Similar symptoms can be caused by problems with the valve body, torque converter, low fluid level, or other internal components of the 4L60E. If you suspect a problem with your overdrive or transmission, it's best to have it professionally diagnosed by a qualified mechanic specializing in automatic transmissions. Ignoring the problem can lead to more extensive and expensive repairs.
