[Jaystroh]

So I’ve been feeling out this car now for a bit since the new trans flush a couple months ago. No more shudder during driving speed but do feel it occasionally when it downshifts or changes v4-v6. Still much better since the flush. I’m wondering about the torque converter though. I’ve got 46,000 on it and I’m pretty sure I was the first fix for the flush at 44,000. The car seems to really dislike low speed acceleration and lugs and growls pretty bad unless you really give it throttle to force it to downshift. Like the car is in 8th gear even at 35-40 mph? Guess what I’m looking for is other people’s thoughts on this and if you think the torque converter is glazed from the wrong fluid being in it up to 44,000 miles or is this something these trans just do? Slow cruising around town or light to light just seems really sloppy with this transmission. Driving it hard and at highway speed it’s pretty much fine. Anyway just wanted to see what everyone thinks. Thanks! Stay safe out there!

[cmitchell17]

Originally Posted by Jaystroh

So I’ve been feeling out this car now for a bit since the new trans flush a couple months ago. No more shudder during driving speed but do feel it occasionally when it downshifts or changes v4-v6. Still much better since the flush. I’m wondering about the torque converter though. I’ve got 46,000 on it and I’m pretty sure I was the first fix for the flush at 44,000. The car seems to really dislike low speed acceleration and lugs and growls pretty bad unless you really give it throttle to force it to downshift. Like the car is in 8th gear even at 35-40 mph? Guess what I’m looking for is other people’s thoughts on this and if you think the torque converter is glazed from the wrong fluid being in it up to 44,000 miles or is this something these trans just do? Slow cruising around town or light to light just seems really sloppy with this transmission. Driving it hard and at highway speed it’s pretty much fine. Anyway just wanted to see what everyone thinks. Thanks! Stay safe out there!

I am kind of in the same situation, I have a 2017 and the first flush fix was done. After a while I think I could kind of feel it come back but not as bad. I changed the calibration with HP Tuners to not allow slip during TCC lockup. This fixes the issue by not allowing it to happen but you do get an increase in NVH (noise vibration and harshness) most people would not notice the increase in vibration and slight noise from having zero slip in the TCC.

Given that its at such a low RPM and relatively lower torque I think the clutches will be fine. I'm not sure if the regular clutches in the transmission are effected the same as the TCC clutch though.

I think the slip you would be more worried about would be the higher RPM WOT slippage or slip you would get when towing, the very light throttle cruise (where this problem happends the most) just dosen't create that much heat. Heat is usually the problem, just like your body can take a lot of volts (getting shocked by a spark plug wire, although it won't feel good) or a lot of amps but not at the same time. It takes the combination of the 2 to hurt you and cause damage generally speaking, and the damage is caused by burns and heat (from the internal resistance of your body).

That being said I would still like the final fluid flush fix to be performed, mostly in hopes that it would improve shift quality overall. The root cause of the issue is supposed to be from the fluid being more unacceptable to dissolving in water. Most fluid should not (think oil and water don't mix). The water comes from humid environments (the southeast in the summer) and the water changes the friction properties of the fluid, so how good it helps the clutches bite and hold onto one another. The calibration (adjusting the pressures and PWM signal to the solenoids to control the pressures) i'm sure was not an easy task so the TCC clutch becomes really sensitive at the low rpm cruising range where it slips a lot.

As far as the sloppy and jerkiness of the 8L90 I completely agree with you there. The 2 piece driveshaft and extra backlash in the ring gear and pinion dosen't help either. These cars are almost a nightmare to drive in slow stop and go, parking lot traffic given the slops and clunks. I am waiting to get the new flush procedure done though in hopes that maybe it can help some of this (unecessarily harsh low speed/throttle shifts, etc.)

[HCI2000SS]

So when they did the fluid and flush, they found no shavings in the fluid? In my case that's exactly what they found, so they immediately replaced the converter. Also in my case we (my tuner and I) found the switching in and out of V4 was simply engine harmonics and not TC slippage.

[ScatPack]

Its not the trans. Its the TC.

[Jaystroh]

I think the TC is slightly damaged but the dealership didn’t mention any shavings or anything for that matter. Just drive it 200 miles and let us know if it still shudders. Which it doesn’t really shudder anymore so I’m sure it’s gonna be a little tricky getting them to replace the TC without the shudder. Have to wait and see. I’ve driven other a8 vehicles and didn’t notice as much shift noise or lugging when slowing/acceleration. Pretty noticeable in the Camaro compared to other cars. Not unbearable though. The other thing I noticed is at 70 on the highway I can be driving for ten minutes on cruise or without and eventually it shifts one last time (assuming 8th gear) weird. The last noticeable thing is driving in my dads neighborhood you have to go 15-20mph and it will surge (tach) like 3 times in a row kinda of throwing you back toward the seat like it’s trying to rev itself up to shift over and over and eventually stops or shifts I don’t know. That’s about the extent of it. Other than that great car. Lol.

[JT58]

My 2017 had the shudder and slippage real bad. They had to replace the converter after only 6K miles and 9 months owning the car. The 9 months include it being at the dealership 2 months not driven getting flushed multiple times and getting the converter replaced. I don't know how it performed after the converter was changed out, i was so frustrated at the time I traded in the car as soon as I picked it up. I have to assume the shuddering, slipping really damages the converter.

[Jaystroh]

Yea I hear ya. I will def figure something out before the power train warranty expires. Kind of a shame because everything else about the car I love! Sucks that they have so many issues with this trans. Lot of talk on here about AFM delete and aftermarket torque converters etc.. that’s all fine but GM parts should be good to go and if not they should fix it correctly. Not bandaid style. I’d expect temperamental things like this in my 600hp supercharged WS6. Comes with the territory in a car like that but not on a modern/new stock vehicle. Sports car or not.

[Jaystroh]

When you got rid of it was that the first time they did any of the work to it? Flush and TC? Or did they do flushes prior to that that didn’t fix it. Just curious if they had to do multiple flushes before they agreed to swap your torque converter. I’ve only had the one flush with the new Mobil 1 fluid. they wouldn’t even mention the TC on the first try lol!

[arpad_m]

Originally Posted by Jaystroh

When you got rid of it was that the first time they did any of the work to it? Flush and TC? Or did they do flushes prior to that that didn’t fix it. Just curious if they had to do multiple flushes before they agreed to swap your torque converter. I’ve only had the one flush with the new Mobil 1 fluid. they wouldn’t even mention the TC on the first try lol!

The current and apparently working fluid was released in Jan 2019, so it's very likely that he got at least one or two flushes that didn't fix the problem.

All the frustration about this is completely understandable, we'll probably never know exactly why GM were dragging their feet this bad, apart from the usual and cynical penny pinching argument. It may be true, but then again, it'd be so much better to see actual tech information and assumption of responsibility without the corporate hazing (one can still dream, eh?).

[Jonster]

I'm not sure I have experienced anything shudder wise in my car (2018 A8 2SS), but should I take it into the dealer and get something done regardless?

I'm not sure how dealers are handling this...meaning are they proactively making this change regardless if the issue exists or is it only if the problem occurs?

[Azerlazer26]

Originally Posted by Jonster

I'm not sure I have experienced anything shudder wise in my car (2018 A8 2SS), but should I take it into the dealer and get something done regardless?

I'm not sure how dealers are handling this...meaning are they proactively making this change regardless if the issue exists or is it only if the problem occurs?

I went to my dealer back in September and got the fluid flushed out. I had no signs of the shudder but I got it done for the peace of mind.

The latest TSB states that the customer only need to say they have the suffer in order to get the flush complete. There should be no reason for your dealer to take a “joyride” to “diagnose” the issue.

[MANNAXMAN]

Originally Posted by Azerlazer26

I went to my dealer back in September and got the fluid flushed out. I had no signs of the shudder but I got it done for the peace of mind.

The latest TSB states that the customer only need to say they have the suffer in order to get the flush complete. There should be no reason for your dealer to take a “joyride” to “diagnose” the issue.

True, there should be no reason for your dealer to diagnose given what the TSB states. However, there are dealerships that will refuse to do the service without first diagnosing it. And GM/Chevy Customer Service is of no help. I know this from experience.

[Spartan268]

Originally Posted by Jonster

I'm not sure I have experienced anything shudder wise in my car (2018 A8 2SS), but should I take it into the dealer and get something done regardless?

I'm not sure how dealers are handling this...meaning are they proactively making this change regardless if the issue exists or is it only if the problem occurs?

Mileage will vary with the dealership. The one I went to never heard of the issue before. They had to get two techs and supposedly the regional master tech to review the issue. Killed about half a tanks worth of gas "diagnosing" and then proceeded to tell me it might be normal. Eventually they did flush the fluid. I even provided them with the TSB number prior to the visit and it's like it hurts their ego that the customer is capable of findings the issue/solution before they get their shot.


If your dealership takes your word for it then you got a good place.

[Azerlazer26]

Originally Posted by MANNAXMAN

True, there should be no reason for your dealer to diagnose given what the TSB states. However, there are dealerships that will refuse to do the service without first diagnosing it. And GM/Chevy Customer Service is of no help. I know this from experience.

Damn, that sucks... Thankfully, my dealer literally took me the second I called them, no questions asked.

We’re you able to get the trans flush done at a different dealer?