redsoxfan2009

So yesterday I go to leave work and when I put the car in Drive it hesitated for about 4 seconds then banged into gear. It lunged the car forward even with the brake on.
This morning I backed out of garage and when I put into Drive it seemed fine till I went to go forward and it was as if it was in neutral for a short period. Maybe 2 seconds. Anyone experienced this in there car.
Thanks

seCen

Its a fairly common problem. Bring it into the dealership and get them to reflash it. I've done it a few months back and now its occurring again. The car is currently at the dealership with an engine light and I told them about varies transmission problems. Ill get back to you about the violent shift.

sycraft

Let the clutch out smoother...

Orange Z06 Girl

Same happened on both of our transmissions. They reflashed. But they also said it comes from it "learning" how we want to shift....and we "might" spend a lot of time hammering it...lol. They say it's based on the way you drive it.

Dave O

Much discussion about issues such as this in the General Discussion area. It appears there is a torque converter issue with the A8 and the symptoms you mention may be early signs that you are having an issue with it. A few links below:

https://www.corvetteforum.com/forums...ifference.html

https://www.corvetteforum.com/forums...r-failure.html

https://www.corvetteforum.com/forums...a8-issues.html

\Boost Monkey/

Yes, there are TC issues with the early A8 built until about October of 2015.

But, the A8 also is known to slow shift when cold into that first D position of the drive.

iclick

My 12/18/14 build did this until I had the dealer flash the TCM and perform the "fast relearn" procedure back in November. Now it upshifts great under all conditions.

REDBULLIT

And how do you perform the "fast relearn"

767guy

* If your car was built Sept 29th or later you can take it to the dealer and they will perform the fast learn in the service bay......easy

* For 2015 C7 ,A8's built PRIOR TO SEPT 29TH,2014, you will need to get the service manager to give you a copy of GM 14-07-30-001C and do the very lengthy drive procedure OR have the dealership do it.....not so easy !

red 1

Not so easy is an understatement, it takes miles and miles of uninterrupted highway and very little traffic to even try this procedure, a real joke created by GM. When the dealer service manager says whew I don't even want to try anymore of these you know it's a real pain in the a#$.

767guy

iclick

The reference I've referred to in the past is PI1473, but the link I had for it no longer works. I have these notes from that TSB:

Op-Code 2810175 Updated programming 2810175.5 ma9 0341 6589

As I understand it, the dealer's scan tool must be connected to the car's OBD2 port and it performs the relearn in the shop. I think the tech needs to interact with the scan tool during the procedure by changing the gear selector, etc. Also, the A8 fluid needs to be between 167° and 185° before the process can start. Since I've never seen mine get above 150° on the street, even in 100° summer weather, I'm not sure how they did it. I presume they stalled the converter in the shop to heat up the tranny.

iclick

One or more of them are so arcane I don't know where you might do it, especially in a suburban area, unless you had an uninterrupted road where you could safely slow down to speeds unsafe for an interstate, then speed up repeatedly. For example, check out this one:

Lightly accelerate to 65 mph (105 km/h) and coast to
25 mph (40 km/h) (light braking can be applied). Repeat
10 times.

I presume if you interrupt the process along the way, like a stoplight or hard curve, you must start over. For those of you with older cars (built before 09/29/14), to see the TSB do a search here on "14-07-30-001A".

iclick

I need to post a clarification to my reply #7 above. I misread Boost Money's "slow shift" to mean the first 1-2 shift when cold, when he apparently referred to the first cold engagement of Drive. I've had a slow engagement into Reverse (~5 sec.) 1-2x every three months almost like clockwork, but the TCM software update and fast relearn did not fix this issue.