[Spartan268]

Originally Posted by Need4Camaro

I also have a 2 Door G37 Coupe and although the displacement is nearly identical the way they drive is night and day. The G37 seems like it has more low end grunt and harder pull from a dig but on the highway the Camaro wins hands down it just has so much of its powerband that isnt even tapped until you reach nearly tripple digit speeds. The G37 is pulling 3.5K RPMS at 80 MPH and the Camaro is BARELY sitting at 2 Grand... an another thing is you can be moving at nearly 100 MPH in the Camaro and it only feels like you're doing 75.

People who keep dogging these V6's obviously haven't driven one, while they're not a power gobbing SS, they're definitely no slouch either.

Agreed. Not to mention those VQs can take on some of the weaker V8s with no issue too. (I'm looking at you Hemi 5.7). The short gearing makes it really pull for a V6 in the lower speeds up until third gear (60MPH+) where it use to kill me and fall flat. I miss the peppiness at times but my brother has my old car so it's still right around the corner anyways.

Anyways back to topic. I'm leaning on the engine load theory. It could be popping back and forth V4 and V6 mode. The road plays a role in this as well if it has any slight incline or decline. I've only seen it once and I just went on at a quicker speed.

[JT58]

Originally Posted by Rock-It Man

How many miles on the car?

My 2010 A6 did this on the highway, too, but only early on. Don't know whether it's a break-in thing or a controller learn thing, but it went away.

My car has only 1600 miles on it. I don't drive it every day- i rotate with a WRX and drive my C4 on the weekends. I have not even taken it on a trip yet and gone over 70 MPH. From reading the posts I need to take it on a trip and get it up to 80 or so and see how it does. I suspect it's V6 to V4 given how light footed I am driving it and how flat the roads are. ( I drive it easy to save gas as I am saving for retirement and on a strict budget to support my passion of owning nice driving cars and working on my classic C4! If I was not on a budget I would have an SS for sure and get 12 MPG and would not have a care in the world!)

[STEVE41]

Originally Posted by BrianWilcox

On my 2017 SS, I had a shudder and RPM shift up 100-200 during highway steady cruise.

Dealer replaced ALL tranny fluid (power flush) with a new viscosity fluid per GM bulletin.
It worked.

mine does it too, would you happen to know the gm bulletin #? thanks

[JT58]

Well I am going to have to bring my car in for the fluctuating RPM issue. It does it really bad on the highway- maintaining steady 70 or so MPH speed on the highway perfectly flat road every few seconds the RPM jumps 300 RPM, then drops back down. It does it in any gear and even when the cruise control is on. It is not the transmission down shifting either- When I put it in manual mode it holds the same gear and it still does it. It is also not going from V6 to V4, it is in V6- I watched it on the screen staying in V6 mode. It also "shudders" when it goes up and down in RPM so I may have the same issues others with the A8 have described as the "shuddering" issue. It feels like the transmission is slipping. I have stopped driving the car until it's resolved as it did is so bad yesterday my GF was feeling it in the passenger seat. It's only one of a very few cars I ever owned with automatic. I was on the fence when I bought it, now I wish I got the 6 speed manual!

[Mark114]

Agreed that it is time to take it to the dealer. Fluctuating RPM is another symptom of a bad torque converter. They can monitor the TC while driving to verify that it is malfunctioning.

[JT58]

It's going in on the 15th. Dealer wants to do an engine diagnostic? The engine seems fine, seems like it's the transmission to me.

[jimmypop13]

Mine does this and I have 4 cylinder mode disabled. I had the shudder bad and this was how it started. I had the triple flush done under warranty but it still had the fluctuation so now my torque converter will need to be replaced. Sounds like ur on the verge of getting the shudder. You could probably take it in now for the triple flush to see if it helps. They should monitor the torque converter slip while cruising. If it's greater than 10rpm they will do the flush. Mine swings almost 200rpm

[Mark114]

Originally Posted by STEVE41

mine does it too, would you happen to know the gm bulletin #? thanks

I believe the A8 Issue TSB is 16-NA-175.

[JT58]

Dropped my car off at the dealership today. The service tech knew all about the A8 problems, the shuddering, etc. He said it's common in all cars and trucks that use the A8- Camaro, Silverado and Corvette. The first thing they do is the flush- if that does not sure the problem, the replace the torque converter. He said that "GM almost has a handle on it". So if your car is experiencing any of the symptoms of shuddering or transmission slippage in any gear, bring it it while it's under warranty. Even if the flush cures the issue- how durable and how long will the tranny last- especially the torque converter. How often will it need to be flushed to keep it trouble free? Good thing for warranties.

[JT58]

Update- the dealer did the tranny flush and on the way home the converter still seemed to be slipping as the RPM's still fluctuated. Today on the way to work, the RPMS's were steady. It might be temperature related. It seems when it is warmer out and the transmission temperature is hotter the slippage occurs regularly. This morning it was 49 degrees and it seemed to be OK. I am going to monitor it for another 200 miles or so- as the dealer said to- and if it still slips, bring it back again for the torque converter to be replaced.

[SuperSound]

New poll is up in the Ask Al section. The A8 TC shudder made the list this time. Everyone needs to cast a vote so we can get some answers.

http://www.camaro6.com/forums/showthread.php?t=518611

[JT58]

What is considered normal threshold for slippage in 7th and 8th gear? After the flush the car shifts smoother and easier than before. I still see some slippage- like when it is in 8th gear at 50-55 MPH and RPM's are say 1500-1600 I still see the tach will hold steady, then jump like 50 RPM, then back. Not nearly as much as before. If you have an A8- does your tach stay at a steady RPM and no fluctuation at all or do you see a little bit of fluctuation?

[SuperSound]

New poll is up for Ask Al:

http://www.camaro6.com/forums/showthread.php?t=521560

[init4fun]

Originally Posted by JT58

Is it normal for the RPM’s to fluctuate on the highway in 8th gear going a steady speed, flat surface- say 50, 60 or 70 MPH? I notice on mine that the tach, the RPM’s will raise and lower by 100 or so RPM when I am at a perfectly steady speed holding the gas pedal steady. The tach will go up and down every say 10 seconds- up 100 RPM, then down 100 RPM. I am guessing that it is 100 RPM, it could be 150 or 200- I see the needle move and can feel the engine RPM's raise and lower.

This is how the torque converter issue first appeared in my car. Steady state driving around 70 mph with cruise set. Tack would shudder about 300 rpm up and down. Eventually it got worse to where you could feel the shudder in the car.