[CHASLT1]

No way i would touch a C7 out of warranty with a A8. Mine started the shudder at 400 miles on my new 2019 C7 and it should have had the latest fluid since it was built in Feb of 2019.

[arpad_m]

Originally Posted by CHASLT1

No way i would touch a C7 out of warranty with a A8. Mine started the shudder at 400 miles on my new 2019 C7 and it should have had the latest fluid since it was built in Feb of 2019.

The newly formulated fluid that solves the issue, along with the requisite trans flush machine and exchange toolkit, began shipping to dealers in late January 2019. The process completed by the end of March 2019. The techlink bulletin about the latest fluid exchange was issued on Jan 31st, 2019.

It is entirely plausible that a vehicle built in Feb 2019 still received the old fluid—after all, I don't think GM would simply have dumped its fluid inventory down the drain, especially since the shudder affects a small percentage of 8L90 transmissions (and more, but still a minority of the lower spec 8L45 units).

[raptor5244]

Originally Posted by CHASLT1

No way i would touch a C7 out of warranty with a A8. Mine started the shudder at 400 miles on my new 2019 C7 and it should have had the latest fluid since it was built in Feb of 2019.

My 2016 2SS A8 started shuddering at about 2500 miles. There was no suggested fix back then so I traded it for a C7 with an M7. Now back in a 2021 ZL1 with the A10 and so far so good.

[mlee]

Originally Posted by 1LEornothing

Not surprised at all about the A8 issues, it is not just GM, several manufacturers have had issues with these 8, 9, 10 speed automatics. More is not always better.

NOT true at all.

The 8 speed is crap with the TC shutter and all, but the 10 speed has been a beast since day one in these cars.

I owned the 2nd production 10 speed for both Ford and GM and currently own another 10L90. Most definitely the automatic transmission of choice these days.

[arpad_m]

Originally Posted by mlee

NOT true at all.

The 8 speed is crap with the TC shutter and all, but the 10 speed has been a beast since day one in these cars.

I owned the 2nd production 10 speed for both Ford and GM and currently own another 10L90. Most definitely the automatic transmission of choice these days.

As quoted above, it seems to be 90-95% the same internally as the 8L90. I'll reread the trans sections of the service manual and promise to come back here to correct myself if that's not the case

We are all glad the 10L90 is such a beast, and I'll generously overlook minor glitches such as the 4-5 shift issues, lack of downhill grade engine braking, gear whine and factory overfilling problems. It is clearly the better transmission (I particularly love the extra gear between the 8L90's 4th and 5th), but the margin is grossly exaggerated. The shudder is the only real issue with the 8L90, there's no denying that GM dropped the ball hard on that one, but apart from that, it's a stout unit.

[There is a huge benefit to information and opinions being so readily available online, but one of the appalling downsides is how the internet magnifies extremes while erasing all subtlety and the middle ground like a pendulum with an excavator bucket attached... A10 = king of torque converted automatics, A8 = crap; ZL1 = royalty, anything less = crap etc. I don't see why the world would need to be binary to make sense.]

[Spaceme1117]

So glad a lawsuit has been filed. Can't wait to get my check 15 years from now for $0.81 and the lawyers get $50,000,000.00. Will be such a win for all the owners affected.

[NashZL1]

^ What he said.

My 2017 Corvette Grand Sport has had no A8 transmission issues in 19k miles. Did have the flush and new fluid exchange done when it became available. I do know several other Corvette owners who had torque converters swapped and other issues.

[Strange Flavor]

I had two flushes and a converter changed by 1200 miles. The shuddering showed up at 400. Definitely a huge issue, and I've had friends that have had the same issues. Funny when I hear things like majority don't have any issues. If I myself and three friends in two separate platforms have had the issue (Sierra, Camaro x2). That seems like a lot in a small sample size. I've had 4L60's give less problems than these and people love to hate those. That aside when the transmission is working it is a beast.

[Camaro fanboy]

mine is perfection. way better then the 6 speed ayto in the gen5

[Fiyero88]

My 2018 Camaro has 40,000 miles on it. In the morning when the engines cold. It will literally almost throw me out of my seat leaving the driveway when it shifts between 1st and second. The dealer said that's normal, I said I've never driven a car that does that. They also did nothing because they said the tech couldn't recreate it. Well no duh they didn't let it sit overnight ��so they wouldn't be able to recreate it.

[mlee]

Originally Posted by Fiyero88

My 2018 Camaro has 40,000 miles on it. In the morning when the engines cold. It will literally almost throw me out of my seat leaving the driveway when it shifts between 1st and second. The dealer said that's normal, I said I've never driven a car that does that. They also did nothing because they said the tech couldn't recreate it. Well no duh they didn't let it sit overnight ��so they wouldn't be able to recreate it.

[arpad_m]

Originally Posted by Fiyero88

My 2018 Camaro has 40,000 miles on it. In the morning when the engines cold. It will literally almost throw me out of my seat leaving the driveway when it shifts between 1st and second. The dealer said that's normal, I said I've never driven a car that does that. They also did nothing because they said the tech couldn't recreate it. Well no duh they didn't let it sit overnight ��so they wouldn't be able to recreate it.

This is absolutely not normal. I had a 2018 V6 2LT with the 8L45 trans, and there was the occasional small clunk with the first 1-2 or R-D shift on cold mornings, but nothing like what you describe.

If not done already, get a transmission flush with the latest 2019 fluid (the applicable technical service bulletin is 18-NA-255), ask the dealer to put the trans in relearn mode and give it a little time to adapt, that may fix or mitigate it to a tolerable level.

My current 8L90 in the 2SS is literally perfect, no clunks, no lurches, no shudder, smooth partial throttle shifts in tour mode, raging beast in sport+performance shift mode at WOT.

[AutoPenalti]

It took 4 dealers for me to finally convince them to band-aid the problem, only for it to occur again a couple of months later. I'm out of the B2B warranty since I'm at 56k miles already on the 2017 A8.

[Fiyero88]

Just left the dealership. They said it's completely normal and the masterechanic came out and said" Chevy designed the A8 poorly, they didn't put a release valve on the A8 so the hydraulic fluid builds up in the mornings and eventually releases causing the car to lunge forward or hard shift. I asked him if it would bother anything and he said Chevy says no it won't ruin the engine. Then he said they designed the A10 to eliminate that problem. But the guy said he's already had headaches with customers complaining about the A10 and he said the A10 will have loads of problems down the line. So basically he's saying that these torque converters are trash. I actually trust him because he works on them all day and really explained to me why the A8 is no good.