maybe for an auto, for a MN7 it works fine.....at least it does for me. I used to not like it but now I use it for all my highway trips.

 

This TSB should brighten the day of all A8 owners..

Tadge " the A8 has been very reliable."

 

Thank you very much for the TSB. I went in with a hard copy of PIP5337D and now have a torque converter on order. I'll take the car in as soon as the part arrives and hope to put this mess behind me.

This experience has been frustrating beyond believe as I've been dealing with a car that is undrivable in V4 mode since December of last year. While the dealership personnel, service writer, service manager and general manager, have borne the brunt of my frustration, the problem lies squarely in GMs lap. Unfortunately for them, they are the face of GM for me when it comes to this car. In fairness to GM, I guess they have been working on identifying the parameters of the defective transmissions and developing a repair strategy, but their silence on the matter has just infuriated me. The only information I received from GM was there is no fix. They wouldn't even acknowledge there was an issue to address.

 

It brightened mine for sure.

 

AFM worked fine for me in my A8 until it didn't.

 

I don't think they measure anything. It sounds like they look at the tach and see how much the RPM varies as the shuddering occurs. At any rate, there at no instructions as how to measure slip.

"Drive the vehicle under the same engine RPM and engine torque as the original complaint in an attempt to duplicate the condition.

Note: If the shudder is only present in 4 cylinder mode and TCC slip is 10 rpm or less deem the shudder concern normal characteristic of AFM.

If the slip speed is beyond 10 rpm or there is shudder during TCC apply the torque converter should be replaced following the instructions published in Service Information (SI)."

 

What does TCC stand for and how is it measured?

Reb

 

Torque Converter Clutch = TCC

I'm not a auto transmission guru, but I think the TCC causes the transmission to lock up when at highway speeds. I believe what happens in a bad A8 is it keeps locking and unlocking and that's what's causing the shudder and RPM fluctuations.

I don't have a clue as to how it's measured except as an increase in RPM as the TCC unlocks the transmission and it slips.

 

I have a new T/C and I'm still having a lower speed like 30-40mph undulating feeling almost like if the wheels are out of round.

 

That's definitely not reassuring! I'm not sure GM has a handle on this now, but I hate driving the car like it is so I'g going for it and hoping for the best.

 

Just dropped my car off at Mak Haik - so far so good - service manager said my car is not right after taking him for a ride and letting him see/feel the issue(better than the first dealer that said car was "in spec").

They also said they store Corvettes inside when they are there for service which was nice to hear - the last dealer returned my car covered in bird droppings

We'll see what kind of repair they do - I gave them a copy of the TSB and they said they were aware of it....

I am cautiously optimistic that there will be a good result from this visit.

 

Mine goes in Wednesday morning. I am also holding my breath. However, there have been several people on here that said the TC replacement fixed the issue, so I'm hopeful. I am more concerned about the quality of work performed than I am about the actual issue. As long as it's in warranty, they can have it until they get it right. It's the collateral damage that worries me. I'm not mad at GM. I've had issues with every major manufacturer. I think the bigger problem is uninformed service departments. Everyone's experience is different. This is a new transmission and GM is at least making progress on the "fix." Is it frustrating? Yes. Is it the end of the world? No. I'll keep my fingers crossed while mine is in the shop and address issues as they arise. If it gets to be too much of a pain, I'll trade it off at some point. It won't be the first time I've lost money on a car.....or the last unfortunately.

 

I had this problem with my 2015, Z-51 vert. The problem first started around 13,000 miles. Took it to the dealer, and the could not see the problem. They told me to keep driving it, and I did. Sure enough he problem got worse and they replaced the torque converter. Have about 4000 miles on the new one, and no problems.

I feel you pain, but it will be taken care of!

 

Almost 5,000 miles on my A6 (delivery date: 2 years ago today) and, thus far, flawless.

 

I am glad GM FINALLY came out with PIP 5337D. This info should help all others with the T/C problem and their dealers have no clue.

 

Don't get your cart before the horse. The new revised torque converters have solved more transmission problems than they haven't. At least these torque converters are failing before your warranty runs out. If we were having these problems after the power train warranty ran out (which I plan on keeping mine past 5 years) I am sure GM would be insisting that we replace the transmission which costs 6K for the A8, without the labor charge.

 

I remember when the A6 was introduced to the 2006 C6. I don't remember any 'growing pains' with the A6 and it's torque convertor like has been shown with the A8 for the past two years.

My belief is that GM will be replacing the A8 with the A10 in their trucks, large SUV's, RWD Cadillac's and Camaro's as quick as they can.

That leaves the Corvette. From the press releases and photo's of the A8, it appears that the A10 has a one piece transmission case and bellhousing(unlike the A8 that is modular in design with a separate bellhousing), thus it is not directly compatible with the Corvette's transaxle.

I don't believe that the low volume of the Corvette with an automatic is sufficient enough to keep the A8 in production after the A10 is in full production, thus GM has to come up with a replacement transmission.

I believe it will be a DCT to replace the A8 in the Corvette. If all the rumors are true about a mid engine car(Cadillac and/or Corvette), and I believe they are, then a new transaxle will have to be designed for that application, and I see no reason that a new transaxle can not be used in a front engine Corvette(to run concurrently with a mid engine car).

I also believe that GM is doing just enough to keep the A8 functioning until it's warranty runs out on cars/trucks currently built/being built. They are not going to do a major redesign the transmission etc to correct any problems since the A8 will shortly be "obsolete".

 

It looks like we are not alone when it comes to A8 problems.
http://www.gm-trucks.com/forums/topi...eal-lemon-law/

 

My SM says the only way to see TCC slip speed is on their scan tool (GM MDI or Tech 2). I don't see a spec on tach variance. Most of those reporting here and on other threads describe large oscillations, like 100-200 rpm, but mine is maybe ±25 rpm, which is barely discernible on the tach with its small 100-rpm graduations. It happens at any time in V4 at steady speed, but shuddering is very rare and when it does occur is temporary (first 10-15 miles of driving).

 

Do they plug the scan tool into the diagnostic port while they drive the car? The RPM in my car varies up and down 400 rpm--200 up and 200 down.

My car doesn't shudder until the car has warmed up--usually just a few minutes after the amber and red lines leave the tach.