GM working on a solution for the A8 Shudder????
 

My service adviser stated that GM is trying to come up with a remedy for those who have gone thru the flushes but have not had their TC changed. She stated that the transmission shop is backed up to December. She also said to try and hang on until it's unbearable. Kind of a sucky answer but she said I'm sorry. I had mine flushed around 6,000 miles and now it's back at the 13,500 miles mark. So anyone heard any thing about a fix that hasn't been discussed here on the forum??

Probably another damn band aid they are coming up with...I doubt there will be any serious fix for these issues in the 6th gen.

Change the Converter and have the TCM tuned to get rid of the slip tables. If not willing to tune, then trade the car. SO far the fluid flush is a band-aid and replacing the converter with a OEM "updated" unit is hit or miss.

I think this is what I am going to do, buy one from Circle D and have the trans tuned.

My service advisor reached out to me, without asking for it, that a new converter and negative/ground cable kit were on order for my car. I also got the same line about the transmission queue being backed up in the shop and I would have to schedule it further out once the parts arrived. But nothing was said about GM TAC continuing to actively work the TSB's for the 8L90. Maybe we'll get the 2019 MQE "improvements" (calibration and torque converter).

At this point I'm wondering what the prolonged exposure to the problem has done to the clutches, bands and valve body. I know it is crazy for GM to swap all new transmissions. But if GM wants the issue behind them, they should look at a rebuild kit to replace clutches, bands, test valve body (replace only if fails), swap torque converter and then update calibration before sticking it in fast adapt learning. May want to check the rear diff while they are at it as well, since fluid contamination would affect it as well.

Wow, Thanks JaxChris. that's great information.

I was under the impression that there was a liquid-to-liquid heat exchanger for the differential cooling. So the “cool” transmission fluid cools the differential, but the fluid is separate (just like the coolant-to-oil cooler for our engines). No way for there to be contamination. Hopefully someone will jump in if I’m wrong. :)

Good call. The transmission lines going to/from the differential is only passing fluid within an internal radiator inside the diff housing.

:happy0180:

Maybe Chevy should instead consider retrofitting A10s into A8 cars that can't be straightened out. Piece of cake mechanically so it should just be an issue of making the 10 speed tranny software work. Even if they wouldn't do it as a warranty replacement they could make it a reasonable cost upgrade for problematic A8 cars.

I have been driving my car around in Sport mode and honestly I don't even notice it doing it anymore. I don't know if it is coincidence or not but I noticed it doing it badly in Touring mode and not at all in Sport.

The problem isn't the A8...the torque converter doesn't like the slipping programmed into the TCM. The fix is a new Converter and tune. Some have fixed their shudder with just tuning alone. I guess it depends on how long you let the shudder go before the converter is toast and possibly even the transmission.

I do agree with you that GM needs to recall this issue because tuning voids warranty and that is really the only way the issue will be fixed as long as the converter and trans are in good working order. The problem is that a recall would likely cost them millions since several platforms have a A8 transmission. So they will continue to band-aid the situation until warranties are up and write the issue off.

The A10 sounds like a good solution but I still have a few concerns. 1 it's not the same A10 as the ZL1. It's a 10l80 which is rated in Newton power less then the 8l90. 2 how is GM handling the TCM tuning on this A10 since AFM will still be present? Will it have the same slip tables in the TCC and end up with potentially the same issue? Had GM done away with AFM on the 19 SS with A10 I would feel a little more confident that it will be a better deal then the A8. I can say I am not hopping on the A10 bandwagon until it proves itself to be worthy.

Could not agree more.

I had the trans flushed with the new fluid at 1500 miles and tuned at 2000 miles, it was and is still 100% perfect with absolutely no issues. Will see how it fares, hopefully the torque converter had not been damaged yet.

(As to drivetrain warranty, my supercharger came with one and it covers the transmission as well, so while it is a limited warranty in terms of max dollar amount, at least I'm not fully out in the open.)

GM flushed the tranny and changed the filter, its perfect now and it was shuddering like crazy. My Camaro used to do that but its been down the drag strip over 180 times so I don't know if it even does it anymore.