ajg617

All of which is very interesting. To add another data point, I talked with my indy, who I trust completely, and he has not changed tranny fluid or replaced a converter on a C6 yet. This mirrors what Eriksson Industries mentioned to me in that the C6 trannies are more robust than the C5s.

And, after reviewing the TSBs, I'm not sure I see anyone that applies to what the OP or I are experiencing, at least for me. There is quite a discussion on AudiZine on this subject, all of which point to replacing the TC. I have no shift problems, no noises. Just cold start 200 RPM surges in 4th, 5th, and 6th depending on the hill I'm going down.

Here's a good thread from audizine. http://www.audizine.com/forum/showth...-at-low-speeds that pretty much sums it up for me.

Not saying that the 9L doesn't have valve body or solenoid problems, but ZF, Eriksson, Nashua Audi, and my indy are all suggesting TC albeit over the phone. I've gone through the TC issues in both my C4 and C5. In the case of the C4, a fluid change solved the problem. In the case of the C5, had to change the TC.

AUJ

In Europe, the skilled diagnostic mechanics are changing the Mechtronic Unit (ZF lingo for valve body) for the definitive fix, with Sonnax solenoids. Many places that service the NAR version are following the trend. The tranny in the C6 Quattros is widely used in many European models and makes; BMWs, Jags, etc. It is ZF's second generation 6 speed for the world. Personally, I think mechanical perfection can not be of this world; striving for expectations that match standards of acceptability are. Whichever way people can attain the level of functionality they expect; more power to them and all the variables that meet those ends to address design imperfections. I am spending time on this topic because C5s are getting to old to own, and the C6's are aging into the point which it may take more effort to keep the herd strong and able, as well as the re-sale price as high as possible.

Also, Sachs makes the right fluid spec (Lifeguard 6) for the ZF 5HP19 for $25 a container via Amazon for free shipping in U.S.A. , for those on a budget with DIY skills.

AUJ

It seems we may have a collective protocol scale developing on this thread by price of intervention and scale up to the big T.C. change for rev flair issues. Fluid/filter change. No work, re-use fluid for rebuilt valve body change with tranny in place. No work, review the cost of the the T.C. change in labor. It requires to drop the box. Some guys can do it proper, DIY; but most may opt for a rebuilt whole unit replacement at a shop or dealership to keep the vehicle. Thanks for the topic, discussion, and research on this topic to all.

am_ver

You mean you saw the RPM needle dance like in this video?
So I had this issue and was able to reproduce this very easily since I live up a hill. When cold and coasting if you don't apply any gas, the rpm needle dances. Audi replaced the TQ convertor, replaced the fluid (twice), upgraded the software - nothing solved the problem.

There is nothing wrong with your TQ convertor - this is something software related (the engine revs up a little) and I have not seen any issues over the last 70k miles since I first noticed this issue.

Audi (including Audi of America) is unable to find the cause for this problem.

ajg617

Yup, that's the ticket all right. Nice to hear you've made it 70K miles. I get it every morning on three different roads -4th gear at 35, 5th closer to 40 - all downhill. Rock solid RPMs if I tap the brakes or apply a little more gas. I don't know if you felt it at 20, but I can sure feel the car 'hit the brakes' with the same frequency. I'm not one for spending a couple of thousand to fix something that can't be fixed and everything else about the tranny is perfect. Would be nice if there was a definitive answer but some things just never get solved.

ajg617

Did Audi change quattro transmissions during the 05-06 model years for the A6? Mine takes Lifeguard 8 but Audi says it's about half and half with the Lifeguard 6 equivalent. If the trans is the same, I wonder why the fluid change since from what I've read, the wrong fluid is something you don't want to do.

Don't worry about the C6 resale price - if you can even find one (at least an Avant any way).

SchwarzS6

Audi did change fluids and TCM software beginning in the 2007 model year. Makes you wonder…

AUJ

Correct. The fluid upgrade is compatible and now recommended specially for the 09L (19A) by ZF per Audi NA. Anyone doing an ATF oil change without a flush and proper drain by disconnecting the return line is only changing half the factory fill anyway.

http://www.zf.com/na/content/media/u...omendation.pdf

By doing a service drain with different fluid, it essentially affects the friction modifier dilution ratio in your box.

am_ver

ZF introduced the Lifeguard8 not Audi. But yes, the 05-6 models did have the Lifeguard6 liquid and then Audi recommended using the ZF 8 fluid for doing flush since it was an improved version and was backwards compatible.

When I first complained of the issue, the first dealer did a flush and used 8 of the G055162A2.

Sub-sequentially, with the TQ converter replacement, they used 4 of the G060162A2 fluid.

And then recently I did a flush, used ZF LifeGuard8 (4.5 liters) - and I can easily reproduce the problem.

Replacing the fluid does not solve the problem.

AUJ

The only time a full fluid change is possible is with a TC change; and yes, ZF introduced the upgrade fluid. Audi changed the requirement on the 09Ls on later models. ZF issued their recommendation for the tranny 09L (19A) per Audi, since the 19A is in Audi products as opposed to the (19). Basically, the ZF 8 is just a lower viscosity fluid with a lot of Group 4 additives that keep the viscosity stable over a long period of time. A similar fluid is produced for the Audi/VW DSG tranny. It is more an evolution of fluids within the industry than anything else. The software flash in the prior posted TSB isto eliminate judder and affects solenoid reaction times. Ergo, it slips the tranny more to give it softer gear engagements, less judder. Not very good as a permanent fix, especially for tranny band life. Many have upgraded their valve bodies and stopped the debate and angst on the issue. If it ain't broke, don't fix it. If it is broke, get it fixed once and for all. In NA, litigation trumps all service decisions. Poor Porsche has to pay out for the plastic coolant hoses used on V8s that was a clear cheap design failure. Americans that buy in the upper segment are increasingly getting more efficient at class action lawsuits. That mentality actually hurts producing real world solutions for everybody else. My 2006 build HYS 19A tranny is running perfect with stock coding with under 50K miles. If it acts up down the road, then the path is set as to how to go about fixing it. That path does not involve a trip to the dealer, or participation in any litigation, for the record.