robert miller

Would have to be a really big problem before a recall. Robert

NSC5

This provides an excellent opportunity to see if "New GM" has become very short-sighted. Old GM would have extended the warranty on these as they did on many issues of the past (6.5 diesel injection pump driver, early Duramax injectors, 3.6 timing chains and tensioners, etc.).

Putting a flawed system on the market is bad act number one but excusable because things happen. Not providing an extended warranty to cover a clear manufacturer mistake is inexcusable and the sort of thing that drives customers to other brands which are all clamoring to gain share. The Corvette converter failures are small potatoes compared to the number of failures across the lines because the 8L90 (and lower torque rated 8L45) are used in a very large number of GM platform/powertrain combinations many of which utilize the same flawed AFM reduced NVH strategy.

tmd937

Does customer service still monitor our forum ? Sure wish they would chime in on the problem but G M might have quieted them down on the forum!

rmorin1249

Don't think we will hear from GM on this issue in this forum. Every TC replacement is costing them thousands of dollars. I see this issue as a big negative for used Corvettes down the road. I know I'm dumping mine before my warranty expires.

tmd937

Can the flush be done in a day or do I need to plan to leave it over night?

tmd937

That is what I am thinking to . I have until Feb of 2019 before my 36 months warranty runs out ! I will either get an extended warrany before then or sell the vette! Very sad as this is my tenth vette!

Maxie2U

I agree.

Many years ago Acura TLs experienced an unusual amount of transmission failures. Within a year they extended the transmission warranty to 10 years/100,000 miles. My transmission failed in year 11 and they still replaced it for free! Now that's a company who stands behind their product.

phisch

I've seen a fair number of threads and posts about torque converter problems with the A8 transmission. Is this the result of a bad batch of TC's out there from GM, or is the underlying root problem with TC failure due to the V8 to V4 switching? If it is the latter, could it be assumed that the TC will eventually need replacing in all A8s?

Classic-Chevy-Guy

Flush is between 2 and 2.5 hours

WelderGuy

It's clearly a design/programming problem. They let the TC lock-up clutch slip a little when the engine is in V4 mode to reduce the pulsing in the drive train. As the clutch wears out, it starts to shudder and let the rpms vary while cruising. Flushing replaces the very slippery original fluid with some that's not quite so slippery, which gives the lock-up clutch a new lease on life in some cases.

If you get a new TC and avoid V4 operation, you'll probably get trouble-free service from the A8 like you would from any other automatic transmission.

HoustonMidtown

My early build 2016 just went in for the 2nd replacement at 29K miles (first one replaced around 15K miles)...

Squeaky Wheel

Does a normally operating C7 automatic transmission exhibit any fluctuations of rpm while driving in the auto mode and cruising at a steady speed? I ask because I’ve seen that on mine, but only in 7th & 8th gear. It stops if I swx to manual mode, and there are no noticeable indications that anything has changed. I’d never know anything was going on if I wasn’t looking at the tach. Everything is buttery smooth.

FWIW, I also have a 2014 V8 Silverado with the 6 speed automatic that cycles between 4 & 8 cylinders and exhibits the exact same behavior. Of course on it you can’t swx to manual paddles.

Red C8 of Jax

When my TC was replaced in 2016, I was informed by the dealer that my TC problem was a result of a bad O Ring. Since the TC replacement ( 22K miles ago) my transmission has been flawless. Just before my 3/36 ran out, I did purchase a GM Extended Warranty. The powertrain warranty does cover you for 5 years, but I plan on keeping my car longer than 5 years.

Red C8 of Jax

I have a 2015 A8. After my TC was replaced, I had NO movement of my RPM's while driving at a steady speed. Prior to my new TC, I had the shudder and the RPM movement at a steady speed. The Service Writer stated that I would have gotten a new TC because of the RPM movement, even if I had not had the shuddering. My new TC was installed in 2016 and now they want to try the flush before you get a new TC.

OVR60

GM knows what the problem is and why don't they get together with the supplier and correct it?

jimmie jam

I have a new CTS4 with the 2.0 turbo AND the 8L45 A8. In just 5,000 short miles this tranny has many of the same issues as the L90. Hard up and down shifts from 1st to 2nd, auto stop bangs into gear so hard that the first time it did that I thought that someone rear ended me...it's like a "bang and then surge". Good thing that it's only a 4 banger so there's no AFM (only on the 6's). I think that this is more of a programing/electronic issue rather than a complete mechanical only issue. Ponderous...

joemessman

Mine never fluctuates in auto mode. See my build date on my signature, etc. It has been perfect for my 48,750 miles. I drive the **** out it. And I did buy the Range device at about 37,000 miles. I forget to use it half the time.

Squeaky Wheel

Care to share with us what GM knows or how it can be corrected?

I find this issue to be quite disturbing. Would not have given the fluctuating RPMs a second thought until reading all these horror stories. I LOVE this car, and want to be able to enjoy it relatively worry free for many many years. Now I'm a bit anxious, and wonder if I'm sitting on a ticking time bomb! Have absolutely no other symptoms of a problem, and don't wish to invite them by tearing into an otherwise healthy unit, but thinking I should maybe get it looked at. At least I'll have something on record. Still 2+3/4 years of powertrain warranty remaining. I'll never hit 60K miles in that period.

HoustonMidtown

The dealer just called - they want to do the flush instead of another TC replacement. He said they called GM tech assistance and they were told fluid change as the first step this time around

trivette

All these comments make me really glad I went against conventional wisdom and bought a first year C7 with the 6 speed auto. I have a longer warranty and not the potential trouble. Despite all the incentives out there now I am not in any hurry to sell/trade mine for a newer one with the potential tranny issue. Given the history of problems one would like to think GM would extend the warranty on these trannys, but we'll see. That definitely casts a negative light on resale value for those equipped with the 8-speed.