[teddyca]

I was confident it was my old wheels and recently installed a new set and its still there so now I am thinking driveline. Car is supercharged and I have driven the thing. I dont track but I will drive spirited. In my old trucks we would look at ujoints and such, is that a thing in the Camaro? I am an A8 and I believe there is some sort of absorber down there.

Heres what the car does. I can be doing 25 or 70 and I will get a rhythmic short vibration and the RPM's sound like the change oh so slightly. Like maybe 50-100rpm's as if the needle just shakes. Clearly I am tuned. Just weird how a vibration changes the RPM slightly. I mean this isnt bad I am just curious. I will live with it if I cant figure it out.

[Simshahh]

Can you log data on your own? If so I would monitor the cam actuator and see what variance there is. While you're at it, monitor TCC slip.

[FlukeSS]

Does it do this at cruise speeds with a steady pedal especially at 70 mph? Does it feel like you are going over rumble strips when it happens? The speed range you are talking about indicates possible A8 Shudder issue.

https://www.camaro6.com/forums/showt...hlight=Shudder

Also if that is the case there is a class action lawsuit against GM for this.

https://www.cohenmilstein.com/sixth-...ssion-lawsuit/

[arpad_m]

Originally Posted by FlukeSS

Does it do this at cruise speeds with a steady pedal especially at 70 mph? Does it feel like you are going over rumble strips when it happens? The speed range you are talking about indicates possible A8 Shudder issue.

https://www.camaro6.com/forums/showt...hlight=Shudder

Also if that is the case there is a class action lawsuit against GM for this.

https://www.cohenmilstein.com/sixth-...ssion-lawsuit/

I don't think Teddy of all members would be unaware of the shudder, plus he is supercharged, so I assume his A8 is also properly tuned (right? RIGHT? ), plus he says he gets the same thing at very low speeds, meaning outside gears 7 and 8. All this is to say I'm not sure this is the shudder.

Originally Posted by teddyca

I was confident it was my old wheels and recently installed a new set and its still there so now I am thinking driveline. Car is supercharged and I have driven the thing. I dont track but I will drive spirited. In my old trucks we would look at ujoints and such, is that a thing in the Camaro? I am an A8 and I believe there is some sort of absorber down there.

Heres what the car does. I can be doing 25 or 70 and I will get a rhythmic short vibration and the RPM's sound like the change oh so slightly. Like maybe 50-100rpm's as if the needle just shakes. Clearly I am tuned. Just weird how a vibration changes the RPM slightly. I mean this isnt bad I am just curious. I will live with it if I cant figure it out.

U-joint on the OEM driveshaft is definitely a thing here, too.

Two quick questions: 1) does your A8 have the latest fluid, and 2) does the frequency of the vibration vary with speed, rpm, or is it roughly constant?

[Rnovrit]

Just a thought. Double check the bolts that hold the axles to the flange at the differential. These are known for backing out and giving vibrations.

[FlukeSS]

Originally Posted by arpad_m

I don't think Teddy of all members would be unaware of the shudder, plus he is supercharged, so I assume his A8 is also properly tuned (right? RIGHT? ), plus he says he gets the same thing at very low speeds, meaning outside gears 7 and 8. All this is to say I'm not sure this is the shudder.

The shuddering is not relative to gears. The speed range for the Shudder is low speed to 70 mph.

At low speed you won't be in gears 7 and 8, but still get the shudder.

I got it at 50mph and 70 mph on my 2016. But it can happen as low as 25-35 mph.

How he describes the symptoms matters.

Again, does it happen while at cruising speeds especially 70mph since he mentioned that speed in particular? Does it feel like rumble strips when it happens? These are key symptoms of the shudder issue. The fact he has a SC doesn't matter and is unrelated. Tuning doesn't change the shudder issue or it shouldn't as the issue is caused by the improper trans fluid. He also never mentioned rather or not he's done any fluid flush yet as per the recall that is specific to these cars. Just because you don't have the problem yet, doesn't mean you won't get it.

Even your car can get it: Just because it hasn't yet doesn't mean it won't get it. Unless during the modification process you changed to aftermarket trans fluid anyways in which case it is unlikely you will have the issue.

[arpad_m]

Originally Posted by FlukeSS

The shuddering is not relative to gears. The speed range for the Shudder is low speed to 70 mph.

At low speed you won't be in gears 7 and 8, but still get the shudder.

I got it at 50mph and 70 mph on my 2016. But it can happen as low as 25-35 mph.

How he describes the symptoms matters.

Again, does it happen while at cruising speeds especially 70mph since he mentioned that speed in particular? Does it feel like rumble strips when it happens? These are key symptoms of the shudder issue. The fact he has a SC doesn't matter and is unrelated.

Well, AFAIK the shudder starts in 7th and 8th, then creeps down to lower gears if left unmitigated, likely beacuse of TCC lockup settings in the tune (this last one I haven't checked personally, it's just my intuition). So I'm thinking if OP had the shudder, he should've experienced it sooner in the 45-75 mph range, hence my question. Still possible, but definitely not 100%.

Originally Posted by FlukeSS

Tuning doesn't change the shudder issue or it shouldn't as the issue is caused by the improper trans fluid. He also never mentioned rather or not he's done any fluid flush yet as per the recall that is specific to these cars. Just because you don't have the problem yet, doesn't mean you won't get it.

Even your car can get it: Just because it hasn't yet doesn't mean it won't get it. Unless during the modification process you changed to aftermarket trans fluid anyways in which case it is unlikely you will have the issue.

Transmission tuning most certainly does change key trigger conditions of the shudder: allowed TCC slip and line pressures. While the stock 8L45 and 8L90 tune allows a lot of slip (several hundred rpms), my tune from Ted Jannetty has the slip set to 0 in all gears and all modes with proper line pressure settings, so the converter clutch never gets the chance to lock, slip and unlock periodically depending on a more hygroscopic fluid's water content.

Also, I have had the proper trans fluid since it became available, so between this and the proper tune I'm banking on never experiencing the shudder. That said, I'll be completely honest and post back if it ever happens.

[FlukeSS]

Originally Posted by arpad_m

Well, AFAIK the shudder starts in 7th and 8th, then creeps down to lower gears if left unmitigated, likely beacuse of TCC lockup settings in the tune (this last one I haven't checked personally, it's just my intuition). So I'm thinking if OP had the shudder, he should've experienced it sooner in the 45-75 mph range, hence my question. Still possible, but definitely not 100%.



Transmission tuning most certainly does change key trigger conditions of the shudder: allowed TCC slip and line pressures. While the stock 8L45 and 8L90 tune allows a lot of slip (several hundred rpms), my tune from Ted Jannetty has the slip set to 0 in all gears and all modes with proper line pressure settings, so the converter clutch never gets the chance to lock, slip and unlock periodically depending on a more hygroscopic fluid's water content.

Also, I have had the proper trans fluid since it became available, so between this and the proper tune I'm banking on never experiencing the shudder. That said, I'll be completely honest and post back if it ever happens.

Fair enough, and ya you'll likely never see the issue then in your case.

2016 SS took my virginity, so I didn't know much about the issue until it happened to me.

And as far as longevity of the issue, it can damage the torque converter if left untreated. So people who had the issue treated per GM and still had the issue had to get the TC's replaced as a result.

So makes sense with what you said about the tuning.

[teddyca]

You guys are fricking awesome and it very well could be a shutter but I thought that was a thing in upper gears so never really considered. Car is tuned perfectly. I have been blown for awhile and this started about a year or 2 ago. Keep in mind I do not drive this car much. I mean its a 2017 with about 30K or so. Hell my 2023 C8 is close to that already . I am now starting to think it could be the trans acting up. I have never done any service on this transmission. I also replaced almost every damn part out back with BMR because the stuff is red and looks cool. Here are my thoughts.

-Check the ujoint and make sure its good
-Check axel bolts (never touched those)
- Fluid flush

Here is another cool situation I am actually in. I have an unlocked A8 TCM from HP Tuners I was going to sell. I didnt think at this point with my C7 back and the C8 both modded I would want to touch this Camaro any longer. Well sh!t maybe get into that fender, replace the TCM and get with Ted. I do have HP tuners for the C7 and Camaro. Might be time. Hell I have always felt the A8 is lazy. Now that I have a C8 as my daily even more so. C7 is manual so can't compare. Off to have a chat with mr. Ted, Plus he has a cool name lol

Fellas I really appreciate you all taking the time to help me out. It really is appreciated and a great conversation.

[teddyca]

Talked to Ted and it seems like a lot to tune these cars. I might have him or my local shop still do it after I am done with my fluid flush. Ordered 8 quarts of the "blue" bottle ATF a filter and gasket from RockAuto for $145 shipped. I watched a recommended video and the guy said "this is a reusable gasket, if it isnt sticking you can reuse. Nah mine is 8 years old, I will spend the extra $30 lol. I'll post up when done with my experience.

As for tuning. Sounds like you need to have your TCM unlocked, HP Tuners MVPK2 or 3, and 4 credits. I do have an unlocked TCM but have a MVPK1 so I might as well just have my shop tune it if they will.

[teddyca]

Welp boys looks like I was dealing with the dreaded shutter. While I was well aware of the issue with these cars I guess I was naive. With such low miles I never even considered it. Last time I got tires on the car, the tech told me one of my wheels was a little tweaked. That was over a year ago so I figured thats what the vibration was. Go figure. And man did I make a mess. I removed the pan after I drained it and left it off overnight with a bucket and cardboard under the trans to catch any drips. My filter shipment was delayed a day, so when I woke up the next morning and went into the garage there was about a half quart on the floor lol. I ended up putting 8 quarts back in the car and it seems perfect. I drove it to Costco today and jumped on the freeway to do so. No shutter and it feels better IMO. I talked to my tuner about tuning the trans and they don't want to. They said its risky business and for me to leave it alone. LOL

I do now have a couple fricking codes. P069E and P0700. I run about 3-4 gallons of E85 mixed with 91 and I am wondering if the FPCM doesnt like that. Sometimes when I think the mix is a little off I will get a CEL, but it goes away when I fill the tank. I might stop doing this. I dont even notice a difference. LOL As for P0700 looks like its a generic code for the TCM. I tried clearing them with a cheap Zurich ZR8 reader and no go. I recently bought a Cread Elite that all the C8 guys live by. I have yet to use it, so I might just make me a cocktail after work and go out there and mess around. LOL

With all that said, THANK YOU fellas for all the input here. I seriously appreciate it.
Teddy

[FlukeSS]

Originally Posted by teddyca

Welp boys looks like I was dealing with the dreaded shutter. While I was well aware of the issue with these cars I guess I was naive. With such low miles I never even considered it. Last time I got tires on the car, the tech told me one of my wheels was a little tweaked. That was over a year ago so I figured thats what the vibration was. Go figure. And man did I make a mess. I removed the pan after I drained it and left it off overnight with a bucket and cardboard under the trans to catch any drips. My filter shipment was delayed a day, so when I woke up the next morning and went into the garage there was about a half quart on the floor lol. I ended up putting 8 quarts back in the car and it seems perfect. I drove it to Costco today and jumped on the freeway to do so. No shutter and it feels better IMO. I talked to my tuner about tuning the trans and they don't want to. They said its risky business and for me to leave it alone. LOL

I do now have a couple fricking codes. P069E and P0700. I run about 3-4 gallons of E85 mixed with 91 and I am wondering if the FPCM doesnt like that. Sometimes when I think the mix is a little off I will get a CEL, but it goes away when I fill the tank. I might stop doing this. I dont even notice a difference. LOL As for P0700 looks like its a generic code for the TCM. I tried clearing them with a cheap Zurich ZR8 reader and no go. I recently bought a Cread Elite that all the C8 guys live by. I have yet to use it, so I might just make me a cocktail after work and go out there and mess around. LOL

With all that said, THANK YOU fellas for all the input here. I seriously appreciate it.
Teddy

I will defer further advice to the other guys, they will be able to help more with the codes than I will.

[teddyca]

I did a bit of research. Pretty sure the E85 is one reason so I will just fill up with 91 and that code will likely go away. As for the P0700 I really hope I didnt mess with that wire when I wiped everything down. I was pretty careful. I mean worst case I read its a $90 part. I will do this all over again and replace the wire. Its not that bad of a job.