A8 Reverse Shift Delay When Cold
11-02-2015, 02:03 PM
#1
Melting Slicks
Thread Starter
A8 Reverse Shift Delay When Cold
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.
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.
Last edited by iclick; 11-03-2015 at 11:23 PM.
11-02-2015, 02:55 PM
#2
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
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
Last edited by Black&White; 11-02-2015 at 02:56 PM.
11-02-2015, 04:06 PM
#4
Melting Slicks
Thread Starter
11-02-2015, 04:12 PM
#5
Melting Slicks
Thread Starter
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.
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.
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.
Last edited by iclick; 11-02-2015 at 04:13 PM.
11-02-2015, 06:23 PM
#7
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.
Last edited by Black&White; 11-02-2015 at 06:31 PM.
11-02-2015, 06:50 PM
#8
Guys, Please go to the NHTSA web site and file a complaint. Mine is below.
http://www-odi.nhtsa.dot.gov/owners/SearchSafetyIssues
http://www-odi.nhtsa.dot.gov/owners/SearchSafetyIssues
Last edited by Black&White; 11-02-2015 at 07:31 PM.
11-02-2015, 07:53 PM
#9
Melting Slicks
Thread Starter
11-02-2015, 07:58 PM
#10
11-02-2015, 08:04 PM
#12
Melting Slicks
Thread Starter
11-02-2015, 08:06 PM
#13
11-03-2015, 04:53 PM
#14
Melting Slicks
Thread Starter
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?
11-03-2015, 07:44 PM
#15
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.
Last edited by Black&White; 11-03-2015 at 07:48 PM.
11-03-2015, 09:39 PM
#16
Drifting
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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.
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.
11-03-2015, 11:18 PM
#17
Melting Slicks
Thread Starter
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.
Last edited by iclick; 11-03-2015 at 11:22 PM.
11-04-2015, 10:28 AM
#18
Read Post #2 Its an email right from a Chevrolet executive.
11-05-2015, 08:55 AM
#19
Melting Slicks
Thread Starter
11-17-2015, 02:26 PM
#20
Melting Slicks
Thread Starter
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.
Last edited by iclick; 11-17-2015 at 02:29 PM.