C7 shudder - again ???
Thread Starter
Advanced
Joined: Jan 2008
Posts: 98
Likes: 6
From: Lakewood Ranch FL
C7 shudder - again ???
2015 C7 automatic, bought new. Now has 27k miles. At about 5k miles I noticed a shudder in the car. Long story short, they replaced (they told me) the torque converter and all was fine. I had one of the early problems before they started just changing the tq fluid.
Anyway, this week I started to notice a similar, but not exactly the same, shudder.
Anyone having this problem? Any ideas before I make an appointment at the dealer?
Thanks
Anyway, this week I started to notice a similar, but not exactly the same, shudder.
Anyone having this problem? Any ideas before I make an appointment at the dealer?
Thanks
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,728
From: Atlanta GA
After they change the fluid , which u will get charged for, get a range device, plug it in and thank me later
The underlying problem is AFM and 4 cylinder mode , stop the car from going into AFM and you will stop the car from shuddering
My 2015 still has the orginal converter and the nasty old "hydroscopic" fluid , AFM tuned out , 52,000 miles and counting ... no shudder
You also can't discount a bad rim or out of balance tire as both can setup a harmonic vibration that can mimic shudder
Dave
The underlying problem is AFM and 4 cylinder mode , stop the car from going into AFM and you will stop the car from shuddering
My 2015 still has the orginal converter and the nasty old "hydroscopic" fluid , AFM tuned out , 52,000 miles and counting ... no shudder
You also can't discount a bad rim or out of balance tire as both can setup a harmonic vibration that can mimic shudder
Dave
Pro
Joined: May 2021
Posts: 500
Likes: 432
From: Queen Creek, AZ
The triple flush, if you haven't already done so, is a must. Next is to eliminate the AFM. That can be accomplished two ways. You can install a Range device or use Manual mode and paddle shift. Both solve the AFM problem. The Range device works great, I know because I used one for quite a while. I had the 9.1 version (latest and greatest) and it worked as advertised. The problem was me. I don't like to introduce aftermarket system "workarounds" unless there is no alternative. In this case there is. I started using the Manual mode, which eliminates AFM and found that I really liked it. There was a bit of a learning curve but the end result was that I used the OEM programming to eliminate AFM and I really enjoyed the feeling of being in control of the car. It has all the positive attributes of a manual shift without any of the negatives. No missed shifts and the shift programming is literally foolproof. Both methods accomplished the elimination of AFM equally well. It really just comes down to personal preference.
Thread Starter
Advanced
Joined: Jan 2008
Posts: 98
Likes: 6
From: Lakewood Ranch FL
Not to my knowledge. They , of course, changed the fluid when they replace the TQ in Feb 2016 with 5600 miles on the car. Where they doing the new fluid at that time?? I think not as that negated replacing the TQ, didn't it?
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,728
From: Atlanta GA
Dave
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
New fluid version came out in 2019. However, you need to call the dealership parts department and make sure they have the fluid in stock (not still using the old stuff). Ask them by part # to make sure. Then, hope they know how to flush it, will take the time to do it as prescribed and not take any short cuts. You're completely at the mercy of the integrity of the service department, the tech and the correct use of latest equipment. GM corporate is not interested at all in the quality of service, or lack thereof, that you get at the local dealer in my experience.
Oh yeah, mine had the shudder after 3, yes 3- different dealerships, triple flushes and it is a ZR1 with A8 transmission. It does not have AFM. AFM is not the only cause of this issue. The fluid is fully capable of causing it all on its own.
Oh yeah, mine had the shudder after 3, yes 3- different dealerships, triple flushes and it is a ZR1 with A8 transmission. It does not have AFM. AFM is not the only cause of this issue. The fluid is fully capable of causing it all on its own.
Last edited by SouthernSon; Aug 27, 2021 at 03:51 PM.
Burning Brakes
Joined: Oct 2014
Posts: 1,057
Likes: 339
New fluid version came out in 2019. However, you need to call the dealership parts department and make sure they have the fluid in stock (not still using the old stuff). Ask them by part # to make sure. Then, hope they know how to flush it, will take the time to do it as prescribed and not take any short cuts. You're completely at the mercy of the integrity of the service department, the tech and the correct use of latest equipment. The fluid is fully capable of causing it all on its own.
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