[whitelightning011]

Had the triple flush done. 90% of the shudder went away, but 10% remains. I called the dealership and they said they will do another triple flush. Is that protocol?

[Darth Martel]

It should be to replace the torque converter

[Darth Martel]

You're correct in your reply. If the torque converters were sound to begin with, there wouldn't be an issue with the slip tables. However, GM's goal with these slip tables is to maximize mpg. They are doing that for all vehicles. All the A8s are experiencing the same issue across the whole GM fleet. The slip tables may not be exact but, they will all have very similar characteristics when it comes to slip and maximizing mpg. GM loves multi-use which is why the same engines and transmissions are used across the board. It's likely that the slip tables are very close as well. I think the main component is the drop in pressure during the slip. I haven't seen the tables and I don't know exactly what's commanded during that slip but, if the shudder disappears with full pressure commanded then it's just a matter of finding the low threshold for the shudder. I wouldn't think 100% pressure is needed. Maybe 50% pressure is all that's needed. Maybe 30%. Who knows. More testing is necessary. And honestly, I don't think it's that important to determine the exact cause. Maybe it's the torque converter. Maybe it's the fluid. Maybe it's the slip table. What's important is finding a permanent fix. GM will never admit to the torque converter being the source of the problem, even if it is. They'll just keep replacing it with a new one until that one goes bad and starts to shudder. If those who choose to mod their vehicles can get rid of the shudder permanently with a tweak to their TCM tune then that's a win. If replacing the stock torque converter with an aftermarket gets rid of it permanently, that's a win. Replacing the stock torque converter repeatedly with the same torque converter every 10k miles or so doesn't seem like a win to me. Eventually they'll stop covering it under warranty and customers get pissed when they have to keep going back to get the same problem fixed over and over. My main point here is to identify what solutions will work permanently. At the moment, GM doesn't have a permanent fix.

Originally Posted by SuperSound

There's a problem with that statement, the issue doesn't affect all vehicles and isn't specific to just the Camaro or even just SS models.

If the slip tables are the cause, then that problem would be evident for every SS at some point. There's not been any evidence beyond it affects a "large portion" of the SS owners. It would also not explain why all the models with the 8L90 including the C7, trucks and SUVs are seeing the issue too since they all use different tuning for the TCM. Now maybe it could be all of them have the same "slip" tuning, but then again would not explain why the failure rate is not higher than it is.

There have been reports of the same issue with the 8L45 as well (probably Caddies too), but as you can see in this thread, there may be 3 or 4 actual LT owners reporting it. Most have symptoms of other trans related issues to point they may be affected by another issue. But if they do indeed have a TC shudder only issue, it would point to the only thing the two variants would have in common....the supplier for the TCs.

To be clear, I'm not saying slip tables are not related. Adjusting them may indeed prevent the issue from coming back, but the evidence we have seen so far points to QC issues with the TCs themselves (hence the multiple revisions, flushes fixing some, not all cars affected, etc...).

It may be a combination too. Slip tables adjusted to maximize FE but weak TC materials in some leading to failures. That might explain why not everyone has the issue. Then again you could be right and the issue will eventually happen to everyone. Differences in driving habits/mileage/time could be the reason only some have reported the issue so far. It's just too early to tell at this point.

[syntaxx7x]

So I got my car back.. was told initially that they will replace the torque converter... but they just did the triple flush.. haven't driven it much, about 20 miles.. but shudder seems to be gone... Tech said I have to drive it at least 200 miles.. if it comes back, just bring it back and they will then replace TC.. *sigh*

He said it was the type of fluid they were using.. *crossing my fingers* hope it's gone..

At least I'm out of the Impala.... now that car sux.. it's a v6 and just got a little more mpg than my SS..

[union894]

I've had the triple flush in the transmission, the rear dif has been changed at least 3 times, which took care of the noise on right hand turns on cool mornings. But now at 10k miles I'm getting the shudder between 51-55 mph, no matter how light or how hard I hit the throttle. This is a never-ending fu#king story! Sick and tired of being sick and tired!

[whitelightning011]

Picked up my car today after having the triple flush done for a second time. We'll see what happens after I drive it around, but I suspect I will feel the shudder once again.

[Kaninux]

Add me to the list (2017 2ss 11k miles) it's currently in for the trans flush this is the third time it has gone in (first two times in for the issue a different Chevy dealer basically did nothing). So next attempt will be the last chance or lemon. Really hope they can resolve the issue love the car, but I'm very doubtful at this point.

[syntaxx7x]

so far about 400 miles in... no shudder...

I'm doing the same thing I was doing before to try and replicate the shudder.. but can't seem to make it happen.. hopefully it's fixed..

Tech said that he did the triple flush and put a different fluid in it.. IDK.. So far it's working.. hope they don't come back.

[2017SSCHIRO]

Originally Posted by syntaxx7x

Who did you write to.. and what did you say..?? They have had my car for 2 weeks.. still haven't gotten to it.. So if it takes a month I would like to know how I could be reimbursed also..

syntaxx7x

Contact GM 866-790-5600 they will assign an Advisor to you and make a case number. they will coordinate with your local dealership to make arrangement for your fix.

I got mine back today. New Torque Converter after 24 days in the shop. The dealership put 200 miles on my car which is shady :( excuse was test drive, wink wink. mileage in 10823 mileage out 11012. Not to mention they bend my driver door where it meets the front driver fender slightly :( going back next Wednesday to have them fix the dent.

Ali

[JaxChris]

Each time mine has gone in I had to go over 1000 miles for the fast adapt learning to finish and the shudder, jerking and clunking on cold starts returned. It has happened 3 times now. The first time they flushed, the 2nd time they did another fast adapt learn and now I'm in a loaner waiting to hear outcome.

I honestly think the lock-up solenoid programming (slip tables) are to blame. Replacing with a good triple disc billet TC would be the best approach, but that voids the entire drivetrain warranty. At this point, I'm more afraid of the car not having a warranty. It all started around 10k miles and I'm now at 20k.

Sadly, GM has a serious reliability report issue with every vehicle running the 8L80/90 transmission. There are frequent reports from Corvette, Camaro, Silverado/Sierra, CT6, CTS & Escalade/Tahoe/Yukon owners. The ATS & Colorado don't have as many complaints, but those two vehicles are also the lowest volumes sellers of the bunch.

I certainly hope each model refresh quickly moves to the 10Lxx replacements. Maybe GM will address the current 8Lxx issues with a better converter and a little reprogramming so we don't have to void our warranties to get these cars running correctly.

And taming the slip tables wouldn't be a bad thing. The converter doesn't unlock properly above 60mph anyways, so there is no interstate coasting to save fuel at the highest drag resistance. Removal of the slip table might drop MPG about 2%, which is nothing compared to losing AFM, which has a 10% MPG bump at 70mph, 20% at 60mph and 30% at 45mph. By the time you hit 85mph, AFM benefits are nullified.

I'd rather lose the slip tables than AFM.

[EFI Tuning]

I will post the tables later today. There is no secret sauce here but it will help show what GM is doing.

Tim

[EFI Tuning]

Here are some captures of the pertinent tables...

In the desired slip table you will see GM allows for a certain amount of slip in the low torque output ranges (ie. cruising, light acceleration). I have these zeroed out on my car for all of the gears.

The ramp rate table applies pressure based on how much current slip there is. The greater the slip amount the more pressure that is applied to bring it to the target slip value. I have this table raised 20% on my car.








Tim

[Natro33]

for those that were in on this thread, please +1 on this one in the feedback to AL forum, thanks. we need more light on this

http://www.camaro6.com/forums/showthread.php?t=510888

[solarstingray]

car s 2 months old with 3k miles and it shudders between gears, feels like im running over road stripes

ill just drive it till it blows up,