A8 Issues
Moderator emeritus
Joined: Jun 2001
Posts: 18,599
Likes: 3,951
From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
Len, honestly, yer confusing the hell out of me! 
If you have the A6 or A8 in "Drive" it will shift back and forth when it feels the urge from V8 to V4. If you have the car set to "Manual", it stays in V8.
I think the poster was referring to the V4 mode as the ECO mode, not necessarily having the Mode switch sitting in "ECO". Now if he was referring to the M7, then ECO is the only way to get to the V4 mode.
Right?
Elmer
If you have the A6 or A8 in "Drive" it will shift back and forth when it feels the urge from V8 to V4. If you have the car set to "Manual", it stays in V8.
I think the poster was referring to the V4 mode as the ECO mode, not necessarily having the Mode switch sitting in "ECO". Now if he was referring to the M7, then ECO is the only way to get to the V4 mode.
Right?
Elmer
Racer
Joined: Oct 2014
Posts: 450
Likes: 122
From: Mount Airy MD
Len, honestly, yer confusing the hell out of me!
If you have the A6 or A8 in "Drive" it will shift back and forth when it feels the urge from V8 to V4. If you have the car set to "Manual", it stays in V8.
I think the poster was referring to the V4 mode as the ECO mode, not necessarily having the Mode switch sitting in "ECO". Now if he was referring to the M7, then ECO is the only way to get to the V4 mode.
Right?
Elmer
If you have the A6 or A8 in "Drive" it will shift back and forth when it feels the urge from V8 to V4. If you have the car set to "Manual", it stays in V8.
I think the poster was referring to the V4 mode as the ECO mode, not necessarily having the Mode switch sitting in "ECO". Now if he was referring to the M7, then ECO is the only way to get to the V4 mode.
Right?
Elmer
I guess I was confused by the comment that "Automatics are in Eco all the time", which, of course, is not true.
Burning Brakes
Joined: Oct 2010
Posts: 833
Likes: 240
Updated trans production date
When did they start using the updated A8 trans? Production date....
Instructor
Joined: Aug 2014
Posts: 159
Likes: 28
From: Williamsburg Michigan
Really??
From the 2015 Owners Manual page 9-42
"ACTIVE FUEL MANAGEMENT (engine cylinder shouts off) 4-Cylinder Mode
Normal with automatic transmission: The engine uses 8-cylinder mode when accelerating, but changes to 4-cylinder mode when coasting.
With manual transmission: Active Fuel Management only active in ECO mode.
Off in Manual mode with automatic transmission unless in ECO mode."
So where did I go wrong???
"ACTIVE FUEL MANAGEMENT (engine cylinder shouts off) 4-Cylinder Mode
Normal with automatic transmission: The engine uses 8-cylinder mode when accelerating, but changes to 4-cylinder mode when coasting.
With manual transmission: Active Fuel Management only active in ECO mode.
Off in Manual mode with automatic transmission unless in ECO mode."
So where did I go wrong???
Melting Slicks
Joined: Apr 2015
Posts: 2,353
Likes: 779
Black&White, our resident transmission issues expert, says it was sometime in October or November of 2015 if i remember it right.
So even early 2016's have the unrevised transmission.
Le Mans Master
Joined: Nov 2015
Posts: 7,382
Likes: 3,501
From: Lake Havasu City Arizona
Racer
Joined: Aug 2007
Posts: 354
Likes: 101
From: Louisville Ky
Don't give black and white a hard time, I went through the A8 battle with GM and finally won and got the trans replaced with the new version and it works great.
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Race Director
Joined: Oct 2005
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From: Plymouth Massachusetts
2025 C7 of the Year Finalist- Unmodified
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Racer
Joined: Oct 2014
Posts: 450
Likes: 122
From: Mount Airy MD
From the 2015 Owners Manual page 9-42
"ACTIVE FUEL MANAGEMENT (engine cylinder shouts off) 4-Cylinder Mode
Normal with automatic transmission: The engine uses 8-cylinder mode when accelerating, but changes to 4-cylinder mode when coasting.
With manual transmission: Active Fuel Management only active in ECO mode.
Off in Manual mode with automatic transmission unless in ECO mode."
So where did I go wrong???
"ACTIVE FUEL MANAGEMENT (engine cylinder shouts off) 4-Cylinder Mode
Normal with automatic transmission: The engine uses 8-cylinder mode when accelerating, but changes to 4-cylinder mode when coasting.
With manual transmission: Active Fuel Management only active in ECO mode.
Off in Manual mode with automatic transmission unless in ECO mode."
So where did I go wrong???
In this instance, when I saw your comment, I'm recalling that when I am driving down the road in Auto, it changes between V4 (ECO) and V8. Therefore (I am thinking, looking at your comment), that the car in most definitely not in ECO mode at all times, since the engine moves from V4 to V8, and V8 to V4, as designed.
My response concerned the comment, "Automatics are in Eco all the time"
I do not disagree with the portion of the manual you provided.
I think we both understand how this actually works. I must have somehow mis-interpreted your comment. Perhaps you can help me with where I went wrong.
Last edited by Len44; Jan 21, 2016 at 02:35 PM.
Melting Slicks
Joined: Apr 2015
Posts: 2,353
Likes: 779
Knowing my A8 could grenade one day when I get in the vicinity of 10k miles (which seems to be the sweet spot for some reason) I want to be ready and I need this info to do so.
So you said it was the TC as the root cause, do you have any idea what exactly or close to the changes were on the revised version? A revised TC only?
Racer
Joined: Aug 2007
Posts: 354
Likes: 101
From: Louisville Ky
Lol, actually, he's the first to bring the information (that I know of) to this forum about the revised transmission, which to me is valuable knowledge. So all joking aside, I consider that a valuable contribution, as is the information about the TC being the root cause.
Knowing my A8 could grenade one day when I get in the vicinity of 10k miles (which seems to be the sweet spot for some reason) I want to be ready and I need this info to do so.
So you said it was the TC as the root cause, do you have any idea what exactly or close to the changes were on the revised version? A revised TC only?
Knowing my A8 could grenade one day when I get in the vicinity of 10k miles (which seems to be the sweet spot for some reason) I want to be ready and I need this info to do so.
So you said it was the TC as the root cause, do you have any idea what exactly or close to the changes were on the revised version? A revised TC only?
My A8 went south at 600 miles, the new trans was finally installed in Dec of 2015 with the new part number along with a new tcm that was replaced the week before the trans.
Last edited by red 1; Jan 20, 2016 at 07:39 PM.
Le Mans Master
Joined: Aug 2015
Posts: 8,243
Likes: 4,617
From: Southwest Florida
Drifting
Joined: May 2015
Posts: 1,412
Likes: 140
Lol, actually, he's the first to bring the information (that I know of) to this forum about the revised transmission, which to me is valuable knowledge. So all joking aside, I consider that a valuable contribution, as is the information about the TC being the root cause.
Knowing my A8 could grenade one day when I get in the vicinity of 10k miles (which seems to be the sweet spot for some reason) I want to be ready and I need this info to do so.
So you said it was the TC as the root cause, do you have any idea what exactly or close to the changes were on the revised version? A revised TC only?
Knowing my A8 could grenade one day when I get in the vicinity of 10k miles (which seems to be the sweet spot for some reason) I want to be ready and I need this info to do so.
So you said it was the TC as the root cause, do you have any idea what exactly or close to the changes were on the revised version? A revised TC only?
Last edited by Black&White; Jan 20, 2016 at 10:50 PM.
