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2005 Volkswagen Passat - CEL

Is this car safe to drive? There’s a fault with the torque convertor that is causing the check engine light. The torque convertor isn’t locking up properly which is causing the warning lights. We had a transmission service/cleaning, but the light came back on, afterward. We are looking at whether it is worth it to rebuild the transmission and replace the torque converter. In the meanwhile, is it safe to drive this care around town? What would happen if the transmission went? Is it worth it to put $3k+ into the transmission?

That is not something someone who is not familiar with your vehicle can answer . Ask yourself is the rest of the vehicle is good shape , has the service schedule been followed , has a mechanic said that other costly things will need to be done soon , do you really like the vehicle , and do you want the cost of replacing it as it now has a very low trade in value .

As for safe , if the transmission does fail it will not be in your driveway but most likely at the worst time.

The torque converter can be replaced without replacing the entire transmission, however the problem might only be the lock-up solenoid, which is much easier and cheaper to replace. In answer to your question, if the car is in poor enough condition/high enough miles that it would be crazy to pay for the repair, you can still drive it until it quits, or until you have to pass an emissions test and can’t.

The torque converter locks up at steady speed to save gas. It won’t hurt anything if it doesn’t lock except you’ll see a slight decrease in mileage. As @bcohen2010 said, it’s probably just the lockup solenoid but depending on the car it might require dropping the transmission to replace it and that can be expensive in terms of labor. You know your car so it’s up to you to decide whether it’s worth fixing or not.

Thanks for the responses. The check-engine light is on, and the error code apparently says the torque converter is cracked. I don’t think the mechanics really look any further than that. do they? The car drives fine, I feel no difference in the shifting at all. My wife is just scared that it isn’t safe to drive, but everything I’ve read seems to say that transmissions don’t go fast, that there will be warning signs, etc. We’re getting quoted $3500 just to change the torque converter, which seems outrageous. “We only use VW parts,” etc. Mechanic seems to think that a cracked torque converter could wreck the transmission, cause it to fail. But that’s not what you think, @davepsinbox_157004?

Yes, it is. You initially said the torque converter wasn’t locking. That’s something you can live with and a whole different thing from it being cracked. If you don’t like $3500–and I don’t blame you, that’s a lot of cash–get another quote from someone else. Get a quote on a used transmission if necessary. Years ago I had a used transmission put in a Pontiac for half the cost of a rebuilt unit. But don’t just let it slide.

There’s no diagnostic code for “torque converter is cracked”, so I’m not sure how the alleged problem was diagnosed. Also, I have never heard of a “cracked” torque converter, and very seriously doubt a car could run and drive fine if this was indeed the problem.

I have, of course, heard of a cracked flex-plate, and that is a common problem on some vehicles. A cracked flex-plate can lead to difficulty starting the engine, often makes noise while accelerating, and may set an error code on some vehicles.

This is an important distinction, because while the torque converter is inside the transmission casing, and immersed in the transmission fluid, the flex-plate is not. I can certainly see how a damaged torque converter could circulate metal shavings/wear particles and contaminate the rest of the transmission, but a damaged flex-plate cannot. If the problem is indeed a damaged flex-plate, I would drive it as long as possible before considering paying the big bucks for the repair.

Did the transmission service seem to improve the symptoms? If so, you might want to try it again. It’s usually not possible to remove all the old transmission fluid on a single service. If your transmission is designed so it allows the pan to be dropped and the filter replaced, that’s the best service method. But that’s not a always possible, depends on the design.