Recently purchased a 2000 A6 2.7T Quattro - AZ car - 125000 miles. The car drives great, shifts when it is supposed to, and is in great shape for a 10 year old car. No leaks anywhere, axels/cv boots in great shape, tracks straight, all options available this car has, and the leather is in great shape. I have a few issues that me and my trusted back yard mechanic are trying to work through - my guy is very reasonably priced that has never steered me wrong - knows more about cars than I will forget in a lifetime. He is trying to approach this from the least expensive solution possible knowing that I don't want to sink more money into this car at this point.

Here are the problems:

- ABS light on threw off code P1606 (ABS modulator needs replaced - sending to Module Master for rebuild - fix is less than $200 for parts). Easy fix.

- the engine light is illiminated and it threw off the code for the torque converter detailed in the title. AZ doesn't get cold enough to have the slipping problems described in other threads - it shifts great, and the tiptronic functions correctly. But the transmission won't kick into overdrive as the solenoid is stuck in the off position. I have spent many hours searching and reading this forum to come up with the following conclusions:

- Torque converters eventually always fail in Audi because the manufacturer says the ATF never has to be changed for the life of the car - this obviously does not have to be true if the ATF and Diff fluids are changed at some regular intervals. Audi "never change" theory seems self serving as the older the fluid gets, the more problems it seems to cause to the internal parts. Case in point, I wanted to get all fluids changed upon purchase, called the dealer for recommendations, and he said the ATF doesn't need changed! Crazy! They are looking to either have the work to replace the tranny or get you to purchase another Audi every 7-10 years.

- You don't have to use Audi ATF if you flush the entire transmission and put in other high quality, but cheaper, ATF. Redline has been highly recommended and probably what I will have put in.

My guess is, based on knowing the guy I purchased this from, that the ATF has never been changed. My other problem is that in AZ you can't get your car registered without the engine light being resolved (can get a waiver to punt the problem down two years, but trying to avoid that as I would like the car to be right).

Finally, the question - I am wondering if I have my mechanic drop the transmission pan, replace the filter, pan gasket, gasket/seal and run all new Redline ATF through the system, flushing a couple times to eliminate any of the bad fluid or other materials floating in there after the last decade of use, is there any chance this will resolve the problem and allow the torque converter to get out of its locked mode? I am trying to avoid the $2500-3000 expense of replacing the converter as that is almost what I have into the car right now. I know that if the torque converter goes unchecked, that it will eventually cause the whole transmission to fail.

Also wondering if I should also have the diff fluids replaced while he is addressing the ATF.

Any guidance or suggestions you may have would be greatly appreciated.

 

Tranny fluid change won't help the TC but is a good idea and should be changed. My car has been throwing the P0741 code with the check in light every 3-4 months for over a year. When I erase the code, the CEL is gone until it returns.

 

I would replace the TCC solenoid first.

However if your mechanic has never done a ZF transmission fluid change you may want to bring it to a good european shop have it changed and have them install a new tcc solenoid.

Otherwise have him read up on the proper way to refill the transmission and check the fluid. I have a thread on my adventure hear somewhere. search for transmission whining.

A very smart thing to do is save every drop of fluid that comes out so you can measure it. (you will need to put at least that much back in) It will take about 6.4L to refill. If you order a kit from Blauparts they only send you 5 Liters so order an additional 2 or 3Liters to be safe in case you spill some.

I would think if solenoid has gone bad it no longer controls the Torque Converter. My Chevy truck had a problem with that solenoid and it caused the converter to lock up, shudder and do crazy things. But it was still trying to work if it wasn't i would expect it to never lock up.

 

A BG flush has kept mine at bay for 8000 miles or so. It only recently has come back and it is intermittent , comes and goes.
I was talking about the 0741 and 17125 TC codes by the way.

 

the tranny doesn't need to come out to replace a solenoid though just drop the pan and replace. If that's what the trouble actually is. who knows the TCM may be registering the converter as locked and assumes the solenoid is bad not the converter.

 

Thanks for all the advice, I am waiting on Module Masters to return my refurbished ABS module. At the point I am having the tranny pan dropped, all the ATF fluid flushed and replaced, and the solenoid tested at that point. Will keep you posted on results.

 

check the price on the solenoid, They probably aren't that much money you may want to have one on hand if you can't spare the car for long. They are usually fairly easy to replace.
also the solenoid controls a valve and some times those valves get stuck but the only way to check the valve is by removing the solenoid and if the solenoid is going to be in your hand you might as well replace it.

 

Is there a update for us? I was wondering how it went cause I was gonna do the same before replacing TC.

My repair shop said the code says its electrical problem. Not TC

 

Just wondering what the outcome of this thread was to resolve the problem.

 

P0741 indicates torque converter clutch circuit solenoid issue or stuck off- probable cause 1) poor electrical connection, 2) failed torque converter clutch solenoid, or 3) blocked oil passage. My 2003 Allroad with 165,000 miles just sent that error message. Car was in Audi dealership for replacement of the secondary water pumps for the turbo, and they replaced the front left axle to fix a vibration issue on acceleration. $2,000. Now 10 days later p0741. Could they have disrupted an electrical connection?