i have 2016 Z51. I just got my car back again 28954 miles. I had 1st flush anout 2 years ago...then it started shuttering again..they flush 3 times with "new" fluids....then another time it had to have transmission computer upgrade. ALLS GOOD? NOPE...well it started again.....yes the shutter is/was back...well they flushed it again with "newest fluid"....just picked it up...5 flushes so far...how many will they do before fixing it ?

 

You may have a problem that can't be fixed by flushing.

For cars made before February (?) 2019, one triple-flush with the new fluid is free if you are under warranty. After that, diagnosis is required for further warranty repair.
The new fluid wasn't generally available until the summer of 2019, flushes before that don't really count.

 

Wasn't there a recent TSB that related to a misalignment issue of the torque tube causing shutter and the need for precision realignment?

 

I had 2 triple flushes that never really fixed the issue of shuddering. I ended up replacing the fluid in the tranny twice myself. I also put in an anti shudder additive. That made a dramatic difference but still noticeable. Then I added in ZMAX transmission additive. My car hasn't shuddered now for months.

 

I just posted this in another thread

I have a 15 , with 46,000 and I still have the orginal fluid , yes that's right lol, the stuff that is not suppose to work because of the wrong friction modifiers and is hydroscopic...
And i might add i drive my car hard ......its not a garage queen

Alot of the problems , now not all...are caused by untrained mechanics who shoot the parts cannon at the trans . GM made the problem worse when the told the dealers to just flush the trans with no diagnosis, if customer said they had shudder then they flushed it

Which led to pissed off customers when the flush did not fix the problem and tons of bad posts about the transmission . Rough engagement , flush it , shift flair , flush it , vibration flush it .....there are 1,000 reasons other than the fluid that would cause these symptoms and GM has a procedure to test for each

My own experence ...I got the shudder ...but mine was right after I installed my new tires ..... exact symptoms... if I did not know better I would have been heading to the dealer and without question they would have done the flush . The reality was it took 3 road force balance tries to get the tires right , not that the first 2 were bad , 3 tires balanced at the low side of the spec and one rear was at the very high side , this caused the harmonic vibration that mimicked the shudder

Moral of the story .... there are other things that can cause a harmonic vibration, tires , rotors BENT WHEELS , torque tube , flywheel .... if they have not fixed it, its because they are working on the wrong thing



Dave

 

i agree...

 

Best thing I did was getting rid of the OEM Pilot Super Sport run-flats and went with Conti Extreme Contact non run-flat. Significant less shudder and so quite.

 

My girlfriend has a 2019 Stingray with the A8. The build date (I think) was January of 2019 & she bought it in May of 2019. She thought that she had the 'shudder' one time, but was not sure. It happened when driving slowly when the car was cold. I drove it more than a few times and did not detect any shudder. I don't have much of a point of reference, though, because my 2017 Stingray has a manual transmission.

When she had about 1,000 miles on her Stingray, I bought her a Range AFM device and installed it. This keeps the car in V8 mode all the time, of course, Both of us have driving the car many times and it is approaching 4,000 miles (GM did a 'free' oil & filter change at 2,800 miles and we will do the second 'free' one this fall when the oil life monitor will start to read low numbers). Should we be worried about having the "right" fluid in her transmission?

It is disconcerting to see this topic keep coming up so often on this forum. Happy Sunday to everyone!!

 

GM did not switch over to the new oil until Feb 1, 2019. You have the old oil.

 

Well, that doesn't sound very reassuring.

Does having the Range AFM device installed full-time mitigate the "shudder" at all? Is a Chevrolet dealership going to "flush and fill" the transmission with the new fluid prior to the warranty expiring? Since we don't put very many miles on it, we're going to run out of "time" long before we reach 36,000 miles (which will take more than ten years at the current pace).

Anybody else with an A8 transmission and a Range AFM device? Did the shudder go away totally with your car?

 

i think latest models already fixed...

 

In my case.NO. It did nothing to address the shudder. A waste of money IMHO

 

I would get the flush with new fluid while you can under warranty. Why wouldn’t you?

 

C8 yes. C7 no

 

Because I told you before , i don't think you have transmission shudder ... if you remember , when you manually shifted that did not stop it either, you had the flush done more than once , you added friction modifier , now a torque converter something else is causing what you are feeling , could be the TCM lockup software which there is an update , could be the torques tube ... anything that rotates

Dave

 

I would definitely recommend the oil change irrespective of whether it would be covered by warranty or not. Their engineers indicated that the oil was too hydroscopic for the trans. Essentially the earlier oil draws moisture from the atmosphere and mixes with the oil This is never good. You would not want to put a quart of water in your engine oil is you were down a quart would you? GM indicated their new oil is "less" hydroscopic than the earlier oil. It's similar to the brake fluid which is hydroscopic and needs to be periodically replaced as well. There are no guarantees replacement will eliminate shutter as there have been reports there are multiple causes for shutter and the oil was just one of them. Some owners here have said it has helped them. So, as they say your mileage may vary but that being said it would be wise to replace the oil. As I mentioned earlier, GM did not switch over to the newer Mobil 1 synthetic until Feb 1, 2019 which was very late in the 2019 model year run. My vehicle was produced on Nov 1, 2018 and I changed the oil. I did notice a moderate improvement in the degree of notchiness I experienced in the first 3 gears (A8). I also had problems with warble and wound up having to replace my rear carrier differential under warranty. My car is now what it should have been new and I am pleased with the vehicle.

 

Yes there are plenty of people who have the range , the problem is with AFM and how the torque converter lock up engages in 4 cylinder mode that causes the shudder ( it does not lock up it pulses )

GM changed the TCM programing and came out with a new fluid to address but the true problem is AFM , cylinder deactivation is not new , its been around since the 80's in Cadillac's and it did not work then and its does not work now .. but auto makers are trying to do everything they can to meet the crazy new CORP fuel economy standard that was mandated by the OBAMA administration

There are 100,000 or more of these transmissions in everything from SUV's to pickups that do not have the shudder but there is a small amount that do ..... and that is the one you hear about so it gives the impression that EVERY A8 is junk when in fact it is the strongest transmission ever made , how many STOCK transmissions can stand up to constant abuse from a 850 to 950 HP engine ... not many

if you don't have the shudder chances are you never will have the shudder , doubled down by the fact you have the range . drive it enjoy it , its a great car

Dave

 

And no one finds trouble with this statement that GM has issued about being Hydroscopic .... LOL LOL

No other transmission made using the same formulation for years has ever had trouble with being the fluid being " HYDROSCOPIC" in nature but now all of a sudden the A8 has an issue with it ... its GM " BULLS&^%$$T .... lol lol

The reason why your 1st 3 gears shift better is because most of the great dealers are doing the ERASE SHIFT ADAPTS and the GARAGE RELEARN procedure along with the TCM firmware update which is all in other TSB;s that address the clunky shifting and engagement issues because of the adaptive learning nature of the TCM controller

Dave

 

We do have the Range AFM device installed in her car - and it stays in there all of the time. If she wants to drive a four-cylinder car, she can use her "daily driver" Audi TT or my Honda Accord. LOL!

Perhaps I will inquire at the dealership when she gets the second "free" oil change done (probably late this fall). Her car was built in January of 2019, so perhaps it has the "old" fluid in it. Even though it only "shuddered" one time (before we plugged in the Range AFM device), it still haunts us just a bit because of the troubles others have had. I also know of countless Silverado owners who have cursed the AFM system for myriad issues. The system in the trucks is similar in nature to that of the one used in the Corvette, so it is likely to develop a lot of the same troubles.

I figured that with fairly easy driving (neither of our C7s will ever see a track), we should not have any issues with it. When spending such good money for a robust car, it ought not to give an owner so much worries during its first few years of ownership, eh?

So glad that I got a stick-shift in my 2017. No need for the "new" transmission fluid or bothering with an AFM device. The engine stays in V8 mode unless I turn the mode selector to "ECO" on the highway - which I don't plan on doing.

P.S. Thanks for your reply!!

 

The only thing I have noticed with my 2019 Stingray A8 is a hard shift from 1st to 2nd when cold....however...yesterday we took the car on a short road trip. By the time we got back home our car was shifting so much better than it did when we left. Actually running smoother bring us to the conclusion it hasn’t been driven enough or too many short trips around town. These cars need to be driven.