A8 shutter at high speed (75+ only)
Thread Starter
Instructor
Joined: Jul 2005
Posts: 215
Likes: 175
From: Jacksonville, Florida
A8 shutter at high speed (75+ only)
I have a 2019 Grand Sport with a shutter at high speed of 75 and above.
Had the Transmission Fluid replaced per the Tech Service Bulletin after 12700 miles
Replaced all four rotors at around 13600 miles
Balanced all four tires also around 13600 miles
Verified Tire Pressure.
Test Drive with Corvette tech at Beaver Chevrolet in Jacksonville, FL.
Still have a light but irritating shutter at or above 75 MPH. The shutter happens regardless of the road surface. The Shutter cycles about every one second from one second smooth to one or two seconds of shutter. Below 70 MPH, the car is smooth.
I drove over 12000 miles on the old type of transmission fluid. Could this be bad tires or possibly a bad torque converter that was damaged with the old style fluid?
Any experience is appreciated!
Cheers,
Mario
AKA Chief G
Had the Transmission Fluid replaced per the Tech Service Bulletin after 12700 miles
Replaced all four rotors at around 13600 miles
Balanced all four tires also around 13600 miles
Verified Tire Pressure.
Test Drive with Corvette tech at Beaver Chevrolet in Jacksonville, FL.
Still have a light but irritating shutter at or above 75 MPH. The shutter happens regardless of the road surface. The Shutter cycles about every one second from one second smooth to one or two seconds of shutter. Below 70 MPH, the car is smooth.
I drove over 12000 miles on the old type of transmission fluid. Could this be bad tires or possibly a bad torque converter that was damaged with the old style fluid?
Any experience is appreciated!
Cheers,
Mario
AKA Chief G
Le Mans Master
Joined: Oct 2014
Posts: 8,662
Likes: 2,722
From: Atlanta GA
I agree ,bent wheel but don't rule out balance . I had to have my tires balanced twice to get rid of my shudder
A lot of dealers jump on the transflush bandwagon when in fact the trans has nothing to do with a lot of the shudder issues . Anything that rotates can setup a harmonic vibration that mimics the transmission shudder especially our heavy Runflat tires that are two different sizes
Dave
A lot of dealers jump on the transflush bandwagon when in fact the trans has nothing to do with a lot of the shudder issues . Anything that rotates can setup a harmonic vibration that mimics the transmission shudder especially our heavy Runflat tires that are two different sizes
Dave
Pro
Joined: Aug 2018
Posts: 652
Likes: 156
From: Clarksville, TN
I've been chasing the same vibe for about a year now and am 90% certain its wheel and or tire related. I think my next step is having the tire rotated on the wheel then rebalanced to see it the vibe changes speed or frequency. I've done multiple road force balancing's without any noticeable change.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 215
Likes: 175
From: Jacksonville, Florida
I've been chasing the same vibe for about a year now and am 90% certain its wheel and or tire related. I think my next step is having the tire rotated on the wheel then rebalanced to see it the vibe changes speed or frequency. I've done multiple road force balancing's without any noticeable change.
Le Mans Master
Joined: Oct 2014
Posts: 8,662
Likes: 2,722
From: Atlanta GA
Good to know I’m not crazy. It’s so frustrating because the tech at dealership won’t test it at high speed. Once he replaced the tranny fluid and the rotors, which solved the vibration under braking, he said nothing is wrong. It’s so frustrating when I get to 75 mph and my high priced sports car shakes more than my Acura SUV.
If so don't let the dealer frustrate you , just take it to them
Also ask them what are the specs on your road force as there is a range . 1st time tech did not rotate the tire as directed , took it to Discount and my rt rear was right at the high side of the spec and all others were at the low side . Once he rotated the tire all was fine and it came in at the low side of the spec as the others , no more shudder
Dave
Last edited by Dcasole; Feb 13, 2020 at 03:50 PM.
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Thread Starter
Instructor
Joined: Jul 2005
Posts: 215
Likes: 175
From: Jacksonville, Florida
do you have a discount tire or a high dollar custom wheel shop near you ?
If so don't let the dealer frustrate you , just take it to them
Also ask them what are the specs on your road force as there is a range . 1st time tech did not rotate the tire as directed , took it to Discount and my rt rear was right at the high side of the spec and all others were at the low side . Once he rotated the tire all was fine and it came in at the low side of the spec as the others , no more shudder
Dave
If so don't let the dealer frustrate you , just take it to them
Also ask them what are the specs on your road force as there is a range . 1st time tech did not rotate the tire as directed , took it to Discount and my rt rear was right at the high side of the spec and all others were at the low side . Once he rotated the tire all was fine and it came in at the low side of the spec as the others , no more shudder
Dave
Mario
Instructor
Joined: Aug 2015
Posts: 115
Likes: 31
If you place the transmission in ‘Manual’, that eliminates the V4 mode and possibility of Shudder. Try this to determine if it’s the trans or wheels/tires.
Try to find a top tier wheel/tire store to check for bent rims & balance your tires. In Atlanta, Butler Tire is the Best! They will check the run-out and rotate the tire on the rim in an effort to get the least run-out & vibration. Done right, there should be no vibration at any speed.
Try to find a top tier wheel/tire store to check for bent rims & balance your tires. In Atlanta, Butler Tire is the Best! They will check the run-out and rotate the tire on the rim in an effort to get the least run-out & vibration. Done right, there should be no vibration at any speed.
Safety Car
Joined: May 2016
Posts: 4,483
Likes: 1,028
From: MN
I like the suggestion above to try M mode to disable V4 mode. Hope this work. If you had bad balance or bent wheel, I would not have expected the shudder to cycle like you mention. With my A8, I could feel a slight effect when V4 kicked in. Good luck!!
Last edited by JonMN; Feb 15, 2020 at 10:06 AM.
Le Mans Master
Joined: Dec 2000
Posts: 5,348
Likes: 3,317
Drifting
Joined: Apr 2013
Posts: 1,743
Likes: 453
From: Saint Clair Shores Mi
I agree, on my Z with a bent wheel, it did have a strange harmonic vibration starting at 38-45 Mph and then again at about 70+. Front left wheel was bent and a small crack. New wheel put on, everything back to normal.
Melting Slicks
Joined: Aug 2016
Posts: 2,761
Likes: 1,016
From: MOUNTAIN HOME Arkansas
If you are a DIY person try moving first the front tires side to side (rotate) to see if there is an improvement. If not, move rear tires side to side. Perhaps the dealer would be willing to chase this problem by doing this for you. Our OE tires are supposed to be rotated (only side to side), every 7500 miles. The tires DO NOT HAVE TO BE BROKEN DOWN, just swapped to other side. They are designed to rotate in EITHER direction. They are marked on the sidewalls, OUTSIDE.If you have aftermarket tires it might be different. Just a thought.👍
Race Director
Joined: Oct 2008
Posts: 16,579
Likes: 7,674
From: NJ
If you place the transmission in ‘Manual’, that eliminates the V4 mode and possibility of Shudder. Try this to determine if it’s the trans or wheels/tires.
Try to find a top tier wheel/tire store to check for bent rims & balance your tires. In Atlanta, Butler Tire is the Best! They will check the run-out and rotate the tire on the rim in an effort to get the least run-out & vibration. Done right, there should be no vibration at any speed.
Try to find a top tier wheel/tire store to check for bent rims & balance your tires. In Atlanta, Butler Tire is the Best! They will check the run-out and rotate the tire on the rim in an effort to get the least run-out & vibration. Done right, there should be no vibration at any speed.
My suspicion is the torque converter clutch was too far gone by the time you had the fluid changed.
What you describe is the tcc shudder.
Or they screwed up the fluid swap (or did a **** job of it.)
Le Mans Master
Joined: Oct 2014
Posts: 8,662
Likes: 2,722
From: Atlanta GA
Not all "shudder" is caused by the fluid or TC
The only way to really find out is for the dealer to do the PICO test which is what all dealers are failing to do as they just automatically blame the fluid which ends up just pissing off a customer when the flush and TCM update does not cure the issue
And .... i know you dont believe this but not all "shudder" is caused by the transmission lol lol
anything that rotates can setup a harmonic vibration that mimics the shudder just as I and others that have posted here have experienced
As i stated above i had my wheels and tires road forced balanced twice but because the 2 front tires and 1 rear were at the low end of the acceptable spec and the other rear was at the high end of the acceptable spec... guess what I had at 65 mph .... shudder vibration that the OP describes above
The only reason why we did not do the PICO is because it started at 25,000 trouble free miles and it started right after I replaced my tires ......
Dave