A6 shifting issue???
Thread Starter
Instructor
Joined: Nov 2007
Posts: 153
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From: Holmdel NJ
A6 shifting issue???
had the vette out today and while cruising in full auto sport mode it hit the throttle at about 25 mph. the car kicked down in first like i intended but instead of shifting hit the rev limiter. as soon as i back off the throttle the car shifted. i found a long empty road and tried to replicate this about 8 times but it only did it one more time---no issue in paddle shift mode though---any ideas or is it time for a trip to chevy??
Burning Brakes
Joined: Jul 2006
Posts: 819
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From: Chambersburg pa.
You said that you were in full auto sport mode at 25 mph and did a full throttle acceleration, right. You mean that you were not using the paddles to shift. Your car down shifted to first as you thought it would. In sport mode using the paddles the transmission acts like a manual transmission, you should have not gotten any down shift. Unless this is where you are having problems then your correct with the probelm. As for hitting the rev. limiter, if you tried to up shift using the paddles during this time the computer will not allow the transmission to up shift until the computer knows that the engine rev's. are in the correct range. All this takes a few seconds so while your waiting for the up shift nothing is happening. Then once the computer sees the engines rev. lower into the safe range it will allow the transmission to up shift. Is this what happened? If so everything is OK if it is as you stated then a trip to you local chevy dealer is necessary. 
Last edited by keg; Aug 2, 2008 at 09:00 PM.
Thread Starter
Instructor
Joined: Nov 2007
Posts: 153
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From: Holmdel NJ
I'm a bit confused. You said that you were in full auto sport mode at 25 mph and did a full throttle acceleration, right. Your car down shifted to first as you thought it would. In sport mode the transmission acts like a manual transmission, you should have not gotten any down shift. Unless this is where you are having problems then your correct with the probelm. As for hitting the rev. limiter, if you tried to up shift using the paddles during this time the computer will not allow the transmission to up shift until the computer knows that the engine rev. are in the correct range. All this takes a few seconds so while your waiting for the up shift nothing is happening. Then once the computer sees the engines rev. lower into the safe range it will allow the transmission to up shift. Is this what happened? If so everything is OK if it is as you stated then a trip to you local chevy dealer is necessary.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
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From: Chandler Arizona
As far as the original problem, I've experienced that a few times. Normally it happens when you don't have good traction and your tires break loose during the downshift and are still spinning when it hits the rev limiter. Since it takes a finite amount of time to complete the shift, the computer anticipates the shift and shifts early. But in this case since the tires are spinning it accelerates more quickly than normal and hits the rev limiter before it can complete the shift.
Happened to me a bunch before I lowered the 1 to 2 shift by 2 mph and 100 rpm using HPtuners.
Burning Brakes
Joined: Jul 2006
Posts: 819
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From: Chambersburg pa.
That is not correct. As long as you don't hit the paddles the Sport mode will act like a full automatic transmission and shift automatically up and down. Once you hit the paddles, you are now stuck in the paddle mode until you shift the tranny back to D.
As far as the original problem, I've experienced that a few times. Normally it happens when you don't have good traction and your tires break loose during the downshift and are still spinning when it hits the rev limiter. Since it takes a finite amount of time to complete the shift, the computer anticipates the shift and shifts early. But in this case since the tires are spinning it accelerates more quickly than normal and hits the rev limiter before it can complete the shift.
Happened to me a bunch before I lowered the 1 to 2 shift by 2 mph and 100 rpm using HPtuners.
As far as the original problem, I've experienced that a few times. Normally it happens when you don't have good traction and your tires break loose during the downshift and are still spinning when it hits the rev limiter. Since it takes a finite amount of time to complete the shift, the computer anticipates the shift and shifts early. But in this case since the tires are spinning it accelerates more quickly than normal and hits the rev limiter before it can complete the shift.
Happened to me a bunch before I lowered the 1 to 2 shift by 2 mph and 100 rpm using HPtuners.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
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Pro
Joined: Oct 2007
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From: Columbus Ohio
My dad's A6 '08 has done this a few times already in just 1800 miles.
Similar scenario, D mode, take a turn at 25 mph (likely second gear), hammer it down, transmission drops to first and the car takes off it begins to spin the wheels and traction control shuts it down... the car then regains traction (we think) and pulls to bounce off the rev-limiter without shifting. He either lets off or it decides to shift we can't remember.
Performance test at GM dealer? Is that a euphenism (sp) ? Here is my near 60K corvette young sir, go run the living @#% out of it and get back to me... Pretty please.
Similar scenario, D mode, take a turn at 25 mph (likely second gear), hammer it down, transmission drops to first and the car takes off it begins to spin the wheels and traction control shuts it down... the car then regains traction (we think) and pulls to bounce off the rev-limiter without shifting. He either lets off or it decides to shift we can't remember.
Performance test at GM dealer? Is that a euphenism (sp) ? Here is my near 60K corvette young sir, go run the living @#% out of it and get back to me... Pretty please.
Last edited by hpfiend; Aug 21, 2008 at 08:46 AM.
Melting Slicks
Joined: Feb 2004
Posts: 2,791
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From: Loudon/Lake Mary Tennessee/Florida
My dad's A6 '08 has done this a few times already in just 1800 miles.
Similar scenario, D mode, take a turn at 25 mph (likely second gear), hammer it down, transmission drops to first and the car takes off it begins to spin the wheels and traction control shuts it down... the car then regains traction and pulls to bounce off the rev-limiter without shifting. He either lets off or it decides to shift we can't remember.
Performance test at chevy dealer is the unanimously recommended fix?
Similar scenario, D mode, take a turn at 25 mph (likely second gear), hammer it down, transmission drops to first and the car takes off it begins to spin the wheels and traction control shuts it down... the car then regains traction and pulls to bounce off the rev-limiter without shifting. He either lets off or it decides to shift we can't remember.
Performance test at chevy dealer is the unanimously recommended fix?
Team Owner
Joined: Sep 1999
Posts: 20,054
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From: Swansea IL
Team Owner
Joined: May 2004
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From: McKinney TX
St. Jude Donor '21-'22-'23-'24
If you've used the paddles while in "S" mode, it will only downshift for you to 2nd when you stop.
Last edited by Vette_DD; Aug 21, 2008 at 09:15 AM.
Le Mans Master
Joined: May 2005
Posts: 6,658
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From: FORT LAUDERDALE FL
after 20 months and 3,000 miles my 07 A6 has, on a few occasions acted very strange. that being said, NEVER while driving like a "normal" person. i suspect that the electronics get spoofed from time to time and this is normal. you have to remember that this car is trying to do many things electronically while it's moving down the road. your PC will do the same thing. i would not worry unless it continues to happen which i bet it will not. 
Advanced
Joined: Jul 2007
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If you've used the paddles while in "S" mode, it will only downshift for you to 2nd when you stop
This is not completely true it will downshift to !st when you come to a complete stop or even close to it like at a couple miles per hour. 2007 a6 car.
This is not completely true it will downshift to !st when you come to a complete stop or even close to it like at a couple miles per hour. 2007 a6 car.
Instructor
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From: Basingstoke England
Le Mans Master
Joined: Apr 2006
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From: The Beautiful Inland Empire WA.
There is another issue that I've not seen mentioned yet.......if the car's computer thinks that a shift to second is going to disturb the car's stability, (i.e. toss the car sideways)...it will hold the car in first gear.
I've experienced this several times while doing a hard acceleration around a corner in first gear.......hit the paddles for second gear, and nothing happens until you straighten out --- THEN the car will let you have 2nd and stop hitting the rev limiter.........
I've experienced this several times while doing a hard acceleration around a corner in first gear.......hit the paddles for second gear, and nothing happens until you straighten out --- THEN the car will let you have 2nd and stop hitting the rev limiter.........
Melting Slicks
Joined: Jul 2007
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From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
From what I've been able to determine at the track, if you get any sort of significant wheelspin it totally confuses the VCM and how the transmission subsequently tries to shift.
If I hook well and launch properly the car will shift properly through all the gears. If I don't hook, then I can pretty much kiss the run goodbye as I'm guaranteed to hit the rev-limiter if I keep my foot on the gas.
I can post up scans from last night at the track if anybody's interested in seeing the difference between a good launch (where the car will shift properly) and a bad one where I hit the rev-limiter.
Christopher
If I hook well and launch properly the car will shift properly through all the gears. If I don't hook, then I can pretty much kiss the run goodbye as I'm guaranteed to hit the rev-limiter if I keep my foot on the gas.
I can post up scans from last night at the track if anybody's interested in seeing the difference between a good launch (where the car will shift properly) and a bad one where I hit the rev-limiter.
Christopher
Team Owner
Joined: May 2004
Posts: 82,175
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From: McKinney TX
St. Jude Donor '21-'22-'23-'24
Absolutely. I've tried it.
