The automatic transmission is quite the engineering marvel when one stops to consider the way in which it operates.
A unit of this type harnesses electrical, mechanical, and fluid power simultaneously to make the most out of every shift, all without any necessary input on a driver’s behalf. This allows motorists to commute from one destination to the next in absolute simplicity.
Contained within the average automatic transmission are many intricate sub-assemblies, such as clutch packs, shift solenoids, and even a specialized fluid coupler, known as the torque converter. However, for all to function as intended, these individual components must operate in harmony with one another.
One particular component that proves especially prone to failure within the automatic transmission is the torque converter clutch (TTC) solenoid. This component is responsible for metering the flow of fluid to a vehicle’s torque converter, thereby regulating torque converter lockup and overall power transfer.
Read on to learn more about the various symptoms associated with torque converter clutch solenoid failure, as well as how to address such issues, should they arise in the future.
What Is a Torque Converter Clutch Solenoid?
A torque converter clutch solenoid is a specialized electromagnetic device that opens and closes in response to requests by a vehicle’s transmission control module (TCM), in order to regulate the flow of transmission fluid to a vehicle’s torque converter.
In turn, the torque converter clutch solenoid plays a pivotal role in facilitating torque converter lockup. However, to better understand this fact, one must first familiarize themselves with the operation of the torque converter itself.
A vehicle’s torque converter is located between the rear (output) end of the engine, and the leading (input) end of the transmission. The torque converter serves as a viscous (fluid) coupling, which effectively disconnects the engine and transmission from one another when sitting idle, through controlled slippage.
As a vehicle reaches higher speeds, ample fluid is directed to the torque converter, facilitating 1:1 lockup. As a result, full engine power is then transferred to a vehicle’s transmission, and slippage is eliminated in its entirety.
As mentioned, this fluid delivery and resulting torque converter lockup, is accomplished through the operation of a vehicle’s torque converter clutch solenoid.
- In the open position, the torque converter clutch solenoid allows fluid delivery to the torque converter allowing lockup.
- In the closed position, the torque converter clutch reduces fluid delivery to the torque converter, allowing controlled slippage to take place.
Torque converter clutch solenoid failure is defined as the inability of the torque converter clutch solenoid to respond as anticipated to TCM commands.
Where Is the TCC Solenoid Located?
The torque converter clutch solenoid is located toward the front end of most vehicles’ transmissions, often directly in front of, or offset from, the transmission’s valve body.
In a number of cases, this solenoid is internal to the transmission housing itself and can be accessed only after dropping the transmission’s valve body/fluid pan.
Bad Torque Converter Clutch Solenoid Symptoms
The presence of a faulty or failing torque converter clutch solenoid is often accompanied by a host of secondary symptoms, some of which tend to be more noticeable than others. Early detection of these symptoms can prove valuable when attempting to make a timely repair.
The following are several of the most common symptoms associated with torque converter solenoid failure.
#1 – Illuminated Check Engine Light
Lack of proper torque converter operation generally results in the storage of one or more active diagnostic fault codes. Therefore, when a vehicle’s torque converter clutch solenoid fails, the illumination of a check engine light should be anticipated.
#2 – Transmission Slippage
If a vehicle’s torque converter clutch solenoid is failed to the closed position, a motorist will often observe transmission slippage at highway speeds.
Oftentimes, this slipping often takes the form of erratic acceleration or hard, inconsistent shifts at higher speeds.
#3 – Stalling at Stops
On the other hand, if your vehicle’s torque converter clutch solenoid has failed to the open position, you might notice that your vehicle begins stalling when coming to a stop.
This is due to the fact that the affected vehicle’s torque converter will remain locked, thereby choking out an engine at lower speeds.
#4 – Activation of Limp Mode
Some vehicles are engineered to enter a derated state of performance if improper transmission operation is detected. This derated state is known as limp mode and often comes as the result of a torque converter clutch solenoid failure.
In many cases, a vehicle will reset from limp mode when turned off, only to re-enter limp mode once more as soon as highway speeds are achieved.
#5 – Shift Abnormalities
In many instances, the failure of a vehicle’s torque converter clutch solenoid will cause a number of shift-related abnormalities.
In some cases, a vehicle’s transmission will refuse to downshift from higher gears, while in others, a motorist might find that their vehicle appears to be stuck in neutral.
Finally, it’s almost certain that abnormally hard shifts will be experienced.
What Causes the Solenoid to Fail?
A torque converter clutch solenoid can fail for a number of reasons. One of the most common causes of failure relates to a lack of proper transmission fluid service.
Burnt, dirty, or otherwise degraded transmission fluid can quickly cause problems within the torque converter clutch solenoid itself, due to fouling and sticking of the internal portion of the valve.
Additionally, a vehicle’s torque converter clutch solenoid can fail at the hands of electrical abnormalities as well. Prolonged periods of high or low voltage delivery to this component’s coil cause eventual failure, thereby limiting or completely compromising the function of the torque converter clutch solenoid in its entirety.
Torque Converter Clutch Solenoid Replacement Cost
The exact cost associated with torque converter clutch solenoid replacement often varies considerably from one make and model of vehicle to the next.
This price differential comes courtesy of varying parts costs and fluctuating labor hour requirements for installation. Therefore, one or more quotes should be obtained for your exact make and model of vehicle before scheduling this type of repair.
Nonetheless, the median cost range for torque converter clutch solenoid replacement generally falls between $300-$750. Of this price, only a fraction ($50-$100) can be attributed to parts costs, while labor tends to command a steeper price of $200-$650.
Can You Drive With a Faulty TCC Solenoid?
While it is often possible to drive with a faulty torque converter clutch solenoid in most cases, doing so is not advised.
If failed to the open position, a vehicle will be prone to stalling at stops, causing hazardous operation. On the other hand, a TCC solenoid failed to the closed position will cause a vehicle’s transmission to slip at highway speeds.
In either case, the possibility of incurring additional transmission damage shouldn’t be ruled out, when attempting to drive for prolonged periods of time with a failed torque converter clutch solenoid.
This is a risk that is best avoided whenever possible, as internal transmission repair is often costly, to say the least.
In any event, the root cause of a vehicle’s TCC solenoid failure should be diagnosed and repaired as soon as possible. Doing so can quite possibly prevent you from being stranded along the roadside, and will minimize the risk of further mechanical issues from arising.
If you’re not comfortable doing the repairs yourself, schedule an appointment with a trusted service center as soon as you can.
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