I've mentioned an odd behavior from my A8 a few times in other A8 threads over the past several months, but haven't seen another account of it reported anywhere. So, I thought starting my own thread on the subject might open up a wider audience. When the car is cold or nearly so, most commonly when first start it in my garage, and then shift from Park to Reverse it will not immediately engage reverse, but will after 5-10 sec. When the delay is in effect the "R" on the DIC turns to orange and blinks about 1-2X/sec., returning to the normal white, stationary "R" when reverse engages. Shifting from "R" to "D" and back to "R" has interrupted the delay in the few times I've tried it. The car has not thrown a code since I've owned it for this or any other issue. On the first instance in April I had OnStar check for codes, and since then have checked it with a code reader I purchased this summer. Nada.

The car was purchased in early Feb. 2015 and the first instance of this behavior happened in early April. It did it 3-4 times in three days, then didn't recur until July, when it did it only once. It happened again about two weeks ago, then repeated the next time the car was started cold one week later. After that, normal. I've tried to record a video but when the camera is pointed at the dashboard it will always be on its best behavior.

At first I thought it was a glitch that would go away with "adaptive learning," but not so far. It isn't a real problem but I would like to know what's causing it. Since the DIC shows an orange, blinking "R" during the delay, that behavior was programmed into the software by GM for a reason, so someone at GM knows its meaning. I've asked three dealers who checked their databases, but none could find anything.

Has anyone else experienced this or heard of it before? I've also experienced one or two of the common oddities known to the A8, but these have disappeared, presumably from adaptive learning. Other than this last lingering glitch my A8 performs admirably.

 

Yes the transmission is faulty. This email is from the the Corvette Brand quality engineer, Jeff Strausser

Regarding your delayed engagement when you first start the vehicle. Give this a try, when you start the vehicle. Wait 30 seconds before moving the shifter out of park. This give the transmission time to fill the torque converter. I recall speaking with you on the converter bleed back condition and a service kit is being release shortly.



Regards,



Jeff

 

I noticed the same thing. I thought it was me. It works fine after a few seconds, but I'm glad to hear I'm not crazy.

Mike G

 

Does your DIC flash an orange "R" until it engages?

 

If its only a matter of the converter filling and doesn't cause any long-term damage, I can live with the quirk. I just want an explanation, and wonder how invasive the "service kit" will be to install? I guess the converter-fill issue is not indicative of low fluid level.

IIRC, your situation was different, was it not? I thought yours was a problem of losing the engagement at traffic lights, which would imply the car has been driven some before the problem starts. Mine is only when cold, the first shift to "R" after sitting overnight or at least several hours.

 

I will check.

Mike

 

I have not noticed the D color. I have had the trans disconnect from drive at slow speeds only to have it then slam back in with great force.

 

Guys, Please go to the NHTSA web site and file a complaint. Mine is below.

http://www-odi.nhtsa.dot.gov/owners/SearchSafetyIssues

 

That's not the problem I'm describing here.

 

So? Report it anyway. The delay engage is also a child of the fluid starvation issue.

 

How often are you seeing this behavior?

 

Is it related? How do we know that? My symptoms and yours are very different. Anyway, I can't submit a safety complaint when I don't have one.

 

Read the email in post#2 from the Corvette brand quality mgr.

 

So both are related to converter "bleed back," I guess, even though symptoms are different. If I have that issue you would think I would get the symptoms you've had, though. I wonder how invasive the "service kit" install is. Has anyone given you any info on that?

 

Yes it all has to do with drive fluid starvation. They are all related symtoms this is why GM is coming out with the check valve kit.

 

Black&white
Ford Expeditions had a similar issue you are describing. The "fix" was a computer recalibration for the transmission. Just a thought. I don't see how a torque converter is going to "drain" with the car being driven.

 

Which issue? Mine (delay to engage reverse when cold) or Black&White's (disengaging at stops and abruptly re-engaging)?

What also perplexes me about the "drain-down" concept is that in my case it only occurs 1-3 times over a period of a few days, then doesn't recur for three months. If it was a mechanical flaw it should happen every time, or at least more often. Does the converter need to be in a certain position? If so, you would think it would be more random.

So far it looks like only Mike has experienced the same issue as me. I'm anxious to know if he's seeing the blinking orange "R" as I am.

If software-related it might be a set of conditions that trigger it, but again you would think it would be more random, not such an odd pattern.

 

Read Post #2 Its an email right from a Chevrolet executive.

 

When was this email originally sent? I wonder what "released shortly" means and how invasive the service will be.

 

To update, when at the dealer for a free oil change last week I mentioned the above issue to the SM again, who still had no answers. He did, however, recommend doing the current TCM software update, which he performed including the fast-learn procedure. The tranny now shifts better without the soft shifts I had been getting mostly when cold. I never had a hard-shift problem and there's no determination yet on the sporadic reverse delay, but time will tell on that. The accompanying docs show #14876, which is described as a fix for the hard-shift problem that I never had. If I get the original issue again I'll report here.