Torque Converter Clutch Problems

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Problem Torque Converter Clutches

torque converter
Torque Converter Clutch

I have written about torque converter clutch problems in other posts but this one will be a little different. Most often when I have a problem with the converter clutch lock up causing an engine stalling condition I find a problem with the tcc solenoid.

However, this is not always the cause of the problem. In fact the last time I faced a converter clutch lock up problem I went for the solenoid right away and it did not fix the issue which was an engine stall only when put into reverse gear. On this particular repair I ran into a clogged transmission cooler.

Although this was the first time I have ever seen this component cause a stalling condition, after checking into the situation it made a lot of sense. The drivers complaint was different this time around then the usual complaint associated with torque converter clutch problems.

The driver stated that the stalling condition was most often when he put the vehicle into reverse. Especially when the engine was cold, like in the morning while backing out of his driveway. In most cases when you have a torque converter solenoid issue the engine will stall as you slow down for a stoplight in a forward gear.

Transmission Cooler Problems

tcc solenoid
TCC Solenoid

Some vehicles equipped with a converter lockup clutch might stall when the transmission is shifted into reverse gear. The cause of this problem might just be a plugged transmission cooler or clogged cooler lines and not the torque converter clutch solenoid.

The reason for this type of torque converter clutch problems is that the transmission fluid normally flows from the converter and directly through the transmission cooler. If the cooler passages are blocked fluid is unable to exhaust from the torque converter and the converter clutch piston can be forced to engage when reverse is selected.

Although as I mentioned this condition is not a common one, the test procedure is not that difficult to perform. It could save you from replacing a good TCC solenoid which on some models is not an easy task. If you want to verify that the transmission cooler is plugged you have to disconnect the cooler return line from the radiator or the external cooler if your vehicle is equipped with one.

automatic transmission cooler
Transmission Cooler

Next you connect a short piece of rubber hose and to prevent it from slipping off the line you can use a couple of hose clamps. Put the end of the rubber hose into an empty bucket or large container. Next you start the engine and with the vehicle in park and the wheels blocked and you measure the amount of fluid that flows into the container after 20 seconds.

A good rule of thumb is that normally 1 quart of fluid should flow into the container in about 20 seconds of run time at engine idle. If less than that has filled the container it may be an indication of a plugged transmission cooler.

Some people prefer to try to clear a blocked cooler by using compressed air. I recommend replacing the cooler whenever possible. But if you do decide to use compressed air make sure you limit the air pressure to below 50 psi or you can cause internal damage to the cooler.

The reason I prefer to replace the part is because the little pieces that are left behind can work their way into the transmission or even clogged the filter. This can cause expensive internal damage to the transmission. A replacement external cooler is around a $100 and can save you a lot of aggravation.

If you are interested in learning more about transmission operation and seeing some common problems with specific models I have a section dedicated to the subject on my you fix cars website. You can learn more about the theory and operation of the torque converter and review some more automatic transmission problems. If you are interested in seeing more recent posts here visit the auto repair information blog homepage.

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9 Replies to “Torque Converter Clutch Problems”

  1. Jonas Brock

    Hi, I have a 1999 dodge Dakota 4×4 5.2 with this very same issue. Only stalls in reverse, and everytime. Tranny shifts great, has a clunk in and out of overdrive. Took it to a reputable tranny shop locally thinking it was such a strange issue. Transmission shop said nothing was wrong with it, and it was an engine problem. Well I went thru the motions. I have a Durango of the same make, year, and model. Swapped a few engine electrical items, with no change. Even changed a connector end on the neutral safety switch because of bear wires. Still no relief. Do you see this issue with dodge trucks often? I’m going to try the suggested test, and put an external cooler on the tranny. Thanks ever so kindly for your time, Jonas Brock Wichita Ks.

  2. Rob

    Mark, I have a 2002 Honda Odyssey, Engine light on, checked at Advanced Auto and reads
    a bad P0740 and P0730 Understand the 740 to be a Torque Converter Clutch repair and the 730 a Gear Ratio problem What would an avg repair cost total job and should i be aware of any other related issues. The van lose gears in forward occasionally and when does shift a very rough and shaking shift. trying to get to repair shop asap… is it drivable without causing further issues or be best to have towed? thanks in advance, Rob

  3. Mark

    Rob: I have never been inside a Honda transmission so I can’t speak as an expert in cost or exact malfunction of your Honda odyssey. But a couple things I would like to mention. 1) Sometimes a torque converter clutch code can be set by other internal problems. 2) Generally speaking driving a transmission with problems can do further damage quickly. I would focus on finding an expert that can be trusted to provide diagnosis and an estimate. With Honda transmissions the people who know them best often work at the Honda dealer.

  4. Randy

    I have a 2002 Subaru Impreza RS with the 4EAT transmission. Ran great no problems with around 180k miles. Pulled into a parking spot the other day, came out and started fine, no codes, shift into drive or reverse and stalls right away. Is this symptomatic of a TCC solenoid failure?

    • Mark Gittelman

      Randy: Yes that is a symptom of a torque converter clutch problem. However, other things can cause the symptoms you described. The torque converter itself can malfunction internally. And of course small vacuum leaks and other issues can cause stalling at idle when load is added. Unfortunately, this will probably take some skilled diagnosis to uncover the root cause.

  5. Randy

    So Mark I have done some more troubleshooting. Drained fluid (looked red and clean) and removed pan. Connector to lock up solenoid has 11.25 volts when key is on and in park. Manual says should be less than 0.5 volts. Does this voltage come directly from the transmission control module? Is it unusual for these to fail?

    • Mark Gittelman

      Randy: “Does this voltage come directly from the transmission control module?” I think it does randy however, I’m not familiar with the failure rate of the TCM on older Subaru’s. The reason I was recommending professional diagnosis is because they would start with a line pressure test and a stall speed test. Important diagnostic information on High mileage transmission.

  6. Ronald Baham

    I have an ’03 Ram 2500 with a Cummings. I had a problem with a shudder between 3rd and 4th gear at low speeds but assumed it was caused by the transmission being built to hold the programmer. Then a couple of weeks ago my girlfriend was driving it. She came to some road construction and stopped. As she and the other cars began to go around the construction, the truck momentarily acted as though the brakes were locked up (tires locked like jamming on brakes) then released, so she pulled to the shoulder of the road. But then the transmission quit pulling all together, forward and reverse. What would be the most common places to start my search for my problem (i.e. Torque converter , tcm, solenoid, etc)?

    • Mark Gittelman

      Ronald: My response would differ with current mileage. The engine in your truck is capable of going hundreds of thousands of miles. The transmission, not so much. With that said, my first step in the situation you described is to take a line pressure test. Low line pressure usually indicates a front pump related problem or deteriorated internal seals bleeding off the needed pressure.

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